But because this is a book by Rebecca Solnit, reflection doesn’t lead toward anything as simple as nostalgia or closure. In her hands the memory of Marine’s death intertwines with an incisive discourse on suburbia and urban decay, with intermittent references to AIDS and nuclear warfare tossed in for good measure. Ian Curtis, the late singer from the new-wave band Joy Division, shares a page with John Keats — Vladimir Nabokov, Djuna Barnes, the Marquis de Sade and Persephone are also brought along for the ride. Interpretive leaps and odd syntheses are Solnit’s stock in trade, and she has earned both devoted readers and critical acclaim by threading together seemingly disparate subjects with a prose style that is at once poetic and sharply analytical.

At a time when the trend in nonfiction publishing favors microhistories — the current file under “C” alone yields popular books on cod, cocaine and caffeine — Solnit’s interests remain expansive. “Wanderlust,” her sprawling history of walking, covered everything from early hominids stepping out on the savanna to latter-day tourists promenading along the postmodern wonderland of the Vegas Strip. Solnit’s “River of Shadows,” winner of the National Book Critics Circle Award for Criticism in 2003, was ostensibly a biography of Eadweard Muybridge, the 19th century photographer who pioneered motion studies and paved the way for cinema, but to Solnit the story of his life telescoped a history of Western modernization. Her 2004 book “Hope in the Dark” took on the abstract notion of hope to reassure peace activists that their protests leading up to the war in Iraq were not for naught. “Victories may come as subtle, complex, slow changes,” she wrote.

In fact, all of Solnit’s books address in some way the vague mechanics of change. “A Field Guide to Getting Lost” is no exception, but where she typically haunts the shelves in dusty corners of the library, here she haunts her past. Drawing on her own well of experience, she explores identity as a process by which we’re always becoming ourselves. Landscapes figure prominently in these autobiographical essays, as they often do in her more scholarly writing: In this case, the places we pass through become a sort of private map, what she calls “the tangible landscape of memory.”

Memory and identity are slippery subjects, to be sure, and at times the book threatens to spin out into the ether. But “A Field Guide to Getting Lost” is never less than brilliant — and neither is the author, as I found out during a recent conversation with her over the phone. I caught her, Solnit explained, at the tail end of a 1,500-mile drive around the West and in the throes of her first cup of coffee in years. What follows are her slightly wired thoughts on the nature of loss and self-doubt, the danger of Bush-era certainties, and the immeasurable value of setting houses on fire.

This book is quite a departure for you. What prompted you to turn inward at this point in your career?

When I finished “River of Shadows,” I was burned out in a certain way. I wasn’t sick of writing books, but I didn’t want to be on contract and on deadline, because that stipulates that you have to know when you start out where you’ll end up, and the book can’t mutate into something different. It can’t be something you don’t know you can do. “River of Shadows” was about doing exactly what I knew how to do best, which is a kind of imaginative but research-based writing that draws from multiple disciplines and sources. But “Field Guide,” like “Hope in the Dark,” which I wrote around the same time, was a foray into a kind of writing I didn’t know I could do. There was a real possibility when I set out to write it that I would fail, that I wouldn’t reach an end. But I wanted to be free to fail.

So the writing itself was an exercise in getting lost?

In some ways. Most of my books have been driven by a linear story. Muybridge was born and then he died, to give you the simplest possible narrative. “Wanderlust” is a moderately chronological survey of the cultural, political, social and spiritual functions of walking. This one was much more intuitive in that things connect to things that lead you to things. The final chapter begins with a dream in which I’m carrying a tortoise in my childhood home. And then it talks about desert tortoises, and then the mythology of desert tortoises by the Chemehuevi, one of the tribes down there in the Mojave, and then it goes on to contrast them with the Death Valley ’49ers — you get the picture. I thought of it as a certain kind of story I hear on the radio sometimes, or something you hear in music, where somebody kind of improvises and noodles around, and there’s often a moment where you think, “Do they have any idea where they’re going? This is so far from where we started out.” And then the last bit falls into place, and you realize that you haven’t just been plodding through the underbrush but you’ve actually been traversing a sort of elegant circle.

It seems like this looser structure allowed you to play around with language, too. All of your books have touches of lyricism, but here it’s foregrounded.

Carrying a linear story requires some straight factual delivery, but this one didn’t have those requirements. You know, you can wax lyrical about how a nuclear bomb is like an exploding sun and ask what it means that we’ve invented all these miniature suns that rain death on Earth. But you also have to explain nuclear fission and uranium, and sometimes you have to shut up with the damn lyricism. One of the big transformations for me came when I was working on my second book, “Savage Dreams,” which is about the Nevada Test Site and Yosemite National Park. I had been writing in these distinct voices, the sort of personal, essayistic voice, the voice of criticism, the voice of environmental journalism. And the test site was such a complex subject that I realized I needed all of them, that it was just an artifice, and an unhelpful artifice at that, to keep them separate. One of the models for me ever since has been conversation. I have these wonderful conversations with friends where we’ll stop and say, “Wait, how did we end up talking about this?” I think everybody has them; it’s how we experience life. We’re always doing this sort of associational jazz riffing, in thoughts and conversation. The rules in writing are usually that you have to be more linear, but, you know, why?

Given that you used your personal history as source material, was there a therapeutic quality to the writing? Any moments of discovery or surprise, where you realized you had stumbled upon terrain you weren’t necessarily prepared to confront?

“Field Guide” is a very melancholic, private book, but the deaths and dissolutions it talks about were distant enough that it wasn’t cathartic. So it wasn’t therapeutic in that sense. The most shocking moment for me was when I was writing the third chapter, about my grandmother and great-grandmother. That was the first time I realized that the middle name I’d given up when I was 13 was the name of this great-grandmother who disappeared, a woman whose name I’d never known, or thought I’d never known. Which I kind of love, because it made me complicit in the disappearance in some ways.

You write that “some people inherit values and practices as a house they inhabit; some of us have to burn down that house, find our own ground, build from scratch.” Do you identify with that metaphor?

Oh, absolutely. I’ve probably burned down at least a dozen houses in the course of figuring out who I want to be and what my values are and shedding all the stuff that I inherited that didn’t really work. I think most people go through some version of that. Some people don’t question it because they had a fabulous childhood and their parents gave them exactly the belief system that works for them — which actually seems kind of dull to me, but it does happen. And some people don’t question it even though it doesn’t work that well and they’re not that comfortable in the house. I left home young and did a lot of torching along the way. But I didn’t run away, because running away always implies that someone is trying to stop you. My parents were busy getting divorced at the time, and sometimes it seemed they hardly noticed. It was like, “Oh, you’re independent, that’s great. Send us a postcard.” And that was sort of it for being parented, more or less.

You left San Francisco for Paris at age 17. That must have been a primary experience at being lost in the world, though it doesn’t figure in the book. Why?

Well, I might write about it some other time. I thought about including it, but for various reasons it didn’t fit, maybe because it was so literal. But yeah, I started making plans to leave home when I was in the single digits, and at 17 I catapulted myself out. I didn’t go to high school — I managed to slither around the torment that would have been for a geeky girl like me. I had taken a year of French in junior college, and I’d read all that modernist expatriate literature and had fallen in love with Romanesque and Gothic architecture, and I just knew there was more to life than California suburbia. So I went off to Paris. I was a conservative revolutionary, though. I enrolled in the American University in Paris because I wanted some anchor when I got there. I had never been to Continental Europe, hadn’t traveled by myself in any meaningful way. This was all terra incognita, which, had I been smarter and more informed, should have been terrifying. But it was just that funny way kids are — like, “Oh, pet the lion!”

What did you make of your time there?

It was quite an exhilarating year. I hadn’t really been educated before that, aside from the year in junior college and two years in alternative school, where we mostly talked and hung out, so my education began there. I had wonderful teachers who taught me to read art and literature on multiple levels, and there was nobody to remind me who I was supposed to be, the way your family and the people who grow up with you often do. I think of Paris as getting a sense of a bigger world, of being open, being resourceful. I was really poor — not in some horrific, deprived way, but in a sense in which every cup of coffee, every pair of socks, was a big financial decision. When you’re under 18 in Paris every museum is free, so I could just wander into any museum and see anything I wanted whenever they were open. And just walking the city was a revelation. In some ways the roots of “Wanderlust” were laid in those long meanders in the city. I was still very solitary then, so much that I didn’t realize it was kind of pathetic. I did start coming out of it a bit, but I still had a long way to go.

It’s interesting that many of your subjects tend to be solitary types as well.

Yeah, although I also write about marchers and revolutions and uprisings. I’m fond of those moments when you feel like a member of the public. That’s very much what “Hope in the Dark” is about, the sense of power and belonging that comes from feeling connected to something larger. But that came to me later in life, partly because I didn’t feel empowered personally and partly because it’s not how Americans are educated to experience themselves. We’re trained to be consumers, which is a solitary pursuit in a much more dismal way, rather than to be citizens, which is about how we’re connected. I’m very interested in the social, but I also think solitude is important. I feel like we’re in a world that values solitude less and less and makes less and less room for it. I’ve just come back from my annual circuit around the West, visiting friends. You see these huge tracts of land that are not social spaces, places in which your primary experience might be physical and spiritual, and where all this information that has to do with navigating your way through a social world is totally irrelevant.

Talking about social worlds, I’d like to get your opinion about your emergence as a public intellectual. Do you identify primarily as an activist, a historian, a writer? What do you think people expect from you?

I probably know less than anybody who reads my books what my role is because I’m just someone who put the message in a bottle — although one of the nice things about becoming better known is that you get to see that the bottle actually lands on beaches and people actually pick it up. Because I do have my very strong, very left (or left of the left) politics, people might expect me to advocate for work that has calculable utility. But I think all this activism is about making the world safe for aimless meandering, for watching cloud formations and those sorts of things. I also think that in an accelerated age, just thinking and reading are already radical acts, acts of resistance to that “Go, go, go; earn, earn, earn; spend, spend, spend” kind of pressure people find themselves under.

“Field Guide” is not a rallying cry in the way that “Hope in the Dark” is, but it can be read in a political context. President Bush presents himself as absolutely certain of his convictions and policies, often in defiance of scientific fact or expert opinion or reports from the field. I found myself thinking that this administration has no capacity for being lost, in your sense of the word, and how dangerous that can be.

They’re certainly whacked-out. It’s funny, because they have every reason to doubt themselves, given the way their war is going and how their economy is running and their Social Security reform is being received, but they don’t. Bush is this kind of medieval fanatic with beliefs in revealed truths that must never be questioned, especially the truths that he reveals himself. It’s really frightening that way.

But unless we indulge in conspiracy theories, we have to accept that America reelected this guy — in which case, do you think America has lost its way, so to speak?

There are a lot of ways to talk about the election. One is that the difference between the number of votes John Kerry and Bush got isn’t meaningful in any profound sense. So, you know, fuck that mandate. That’s not a mandate. That’s a dubious, tiny majority in an extremely dubious process that many people chose not to participate in. But I’ve never been one of those people who have been, like, “Oh, I’ve got to move to Canada.” There’s so much I love about this country, starting with the actual countryside. And it’s such a dialectical country: It’s a place where slavery was legal, but the rebel slaves and abolitionists weren’t any less American than the slave owners. Unfortunately, Bush is not a huge divergence from what came before. We’ve been dumb and belligerent and imperialistic and wrong a lot in the last 200 and whatever years. But that’s a big “we”: We’ve also been anti-imperialistic and revolutionary and imaginative and compassionate.

Generally speaking, is your approach to the past sentimental, elegiac, analytical?

Can I just say yes?

Sure, but then I’d have to rephrase the question.

I always think historically. The way to understand something is by knowing where it came from, what it was before, how it got there, this kind of time-based analysis. And that same historical impulse can apply to your own sense of self. I think everybody’s personal past is important to them, although when I was in my 20s, my childhood was much more vivid and emotionally compelling than it is now. I’m in my early 40s, and it’s much further away. You know, you lose your childhood in order to grow up, and this constant arrival is the present. The book is about being “lost” in both senses: “lost” as in no longer there and “lost” as in not knowing where you are. It’s about finding in some way the beauty and melancholy in living with those losses, in coming to terms with uncertainty. You have to let go of a lot of stuff, including versions of yourself and beliefs and delusions that you were right, or you get stuck.