Allen Shawn never drives down unfamiliar roads. If he did, he'd likely have to turn back and return home, for the talismans he carries with him on trips -- Xanax, ginger ale, a cellphone and a paper bag -- are no match for his many phobias. Shawn is scared of bridges, subways, elevators, crowds, planes and large museums. He can't even walk across an open parking lot without becoming distressed. His new book, "Wish I Could Be There: Notes From a Phobic Life," elegantly combines memoir and research to try to understand the reasons for the fears that have ruled his life since he was a young man.

Shawn is a composer of classical music, but may be better known as the son of famous New Yorker editor William Shawn and the younger brother of actor and playwright Wallace Shawn (of "My Dinner With Andre" and "The Princess Bride," among many other projects). The matter of his family name is not merely one of pedigree. His upbringing, as "Wish I Could Be There" shows, encouraged whatever genetic predisposition to anxiety he had. His was a childhood marked by an excess of the usual secrets and lies. There was the matter of the Shawns' "ambivalence" toward their Jewishness -- his mother preferred to identify with her Swedish side rather than her Russian side, and William and one of his brothers changed their name from "Chon" to the decidedly more Anglo "Shawn." There was his mentally ill twin sister, Mary, who, at the age of 8, was sent to a home and seen only once a year.

Then there was his father's own agoraphobia, never discussed among the family but probably inherited and modeled by his son. (William persuaded his office building to maintain one manually operated elevator for his use.) There was his mother's terror of storms, and her habit of ruling little Allen's life with a ferocity matched only by her back-seat driving in taxicabs. And finally, there was the matter of his father's double life with a second "wife," New Yorker writer Lillian Ross. He interrupted road trips for surreptitious visits to phone booths; at home he took Ross' calls on a separate line, vanishing into a closet with the receiver. Yet Shawn did not learn of his father's lifelong affair until he was almost 30, when, he told the New York Times, someone "a bit angry at men ... mentioned it in the context of a speech in which she was speaking disparagingly of the way men behave."

The name "Lillian Ross" is conspicuously absent from "Wish I Could Be There"; so is Jamaica Kincaid, Allen's ex-wife, with whom he has two children. For a man from such a famous family, of whom so much is known, the tactful silence seems almost too coy. But even in this quasi memoir, Shawn wants his privacy. Indeed, as an agoraphobic -- someone who is afraid of both open spaces and enclosed places, who, when asked what he is afraid of, might plausibly reply "everything" -- he is obsessed with control and dreads revealing more of himself than he must. "Severe phobias can bring with them the fear of discovery and of becoming an outcast," he writes. "Shame begins inside, with being afraid to admit, even to oneself, that one is in some respects hampered."

Shawn argues, rather sensibly, that while phobics are predisposed to their anxieties, those anxieties may be triggered and conditioned by environment and experience. "Wish I Could Be There" uses science, clearly put into layman's terms, to talk about the relationship between the mind and body during a phobic episode. Shawn reviews some basic biology lessons about how the brain fires and the mind creates an explanation for the sweaty palms and racing heart -- a "shoot first, ask questions later" scenario. Once you're in the midst of responding to fear, your emotions step in to give you a way to think about and understand the panic: This open field must present a danger, otherwise why would I be having trouble breathing? In this way, a phobic's fears are almost rational; the only other explanation for the body's sudden attack, after all, would be that you were actually going crazy. The circuit is completed when the desire to explain the fear, to create a story around it, winds up reinforcing it.

There are certainly some weird phobias out there -- ephebophobia, fear of adolescents -- but the common ones are, Shawn thinks, common for a reason. From Darwin, he gets the idea that our fears are vestiges of evolution, deformed and out of place in modern times: In open spaces, there is nowhere to hide from attack; in the dark, predators lurk around any corner. Phobias are the cure that has become a disease. (Darwin, too, was terribly anxious, and "would awaken trembling in terror in the night," although in his day he apparently suffered without understanding.)

From Freud, Shawn gets everything else -- notions of trauma, memory, repression and, most crucially, "the insight that we carry our past inside us as a permanent present." He seems eager to redeem Freud's usefulness, bristling that "new books on the brain seem almost mockingly dismissive" of him. Not so Shawn. He dwells on the case study of 5-year-old Little Hans, who "developed a morbid terror of horses" around the same time that his mother had another baby. Shawn admires Freud for recognizing that "Hans's phobia was constructed on top of an evolutionarily primed wariness about animals" while understanding it as "Hans's outlet for the conflicted longings and fears of punishment he hadn't been able to express in other ways."

Shawn has a literary mind, and it is no surprise that he's drawn to such a literary thinker. "Freud's genius revealed that the infinite resourcefulness of the human mind necessitates a greatly expanded concept of what can constitute 'danger.' The fear mechanism constructed for tigers in the forest can be used by humans to fight tigers in the mind." (Feminists take note: Shawn's discussion of hysteria makes no mention of Dora, the patient who famously broke off treatment, and whose story Freud published as his own.) The fact that he "never got over the suspicion" that he caused the birth trauma suffered by his sister might explain his phobias: They could be, as Freud thought, displaced anxieties, "a discharge of fear in a safe place." Still, Shawn wonders, "if phobias are decoys, what will strike us when the decoys are removed? What awaits us in the emptiness of space?"

Shawn's looping, meandering style, with chapters organized by theme ("Father," "Conditioning," "Alone/Not Alone"), sprinkled with anecdotes, invites self-analysis. But Shawn, it must be said, is not a champion storyteller. His subject is always interesting, but his style can be reverie producing. (Occasionally one might reread a paragraph a few times without noticing.) And yet something sinister vibrates underneath. Much like a conversation with an extremely anxious person, the same territory is mined over and over, unearthed from many angles in a search for something -- a definitive cause, a cure -- that can never be found.

In music Shawn found joy and freedom, the ability to experiment and to be dark and daring. "Some lurching hidden tragic power coursed through me and made me shiver and feel that I had been living a very long time." And yet the overall tenor of the book is muted and tender, steeped in quiet reverence for fragile attempts to manage fear and muddle through as best we can. Of his father, Shawn writes that he "tended to treat people the way the character Alyosha in Dostoevski's 'The Brothers Karamazov' recommends: 'like patients in a hospital.'" On the one hand it is true that we are all, as we learned from Freud, sick, and that the best thing we can do with life is help each other through it. On the other hand, we are not, or not only, hospital patients.