By David Gates

Robert Burton began his 1621 "Anatomy of Melancholy," that choke-a-horse compendium of lore about what we now call depression, with an address to the reader: "I presume thou wilt be very inquisitive to know what antic or personate actor this is, that so insolently intrudes upon this common theatre to the world's view..." In "The Noonday Demon," a 21st-century analogue to Burton, New Yorker writer Andrew Solomon makes the same assumption, and if he's holding anything back, it's hard to imagine what. In recalling his own incapacitating depressions, Solomon shares about his sexuality (evenhandedly bi), his drug use (energetically recreational), his therapeutic regimen (a dozen pills a day, which have included Zoloft, Paxil, Navane, Effexor, Wellbutrin, Serzone, BuSpar, Zyprexa, Dexedrine, Xanax, Valium, Ambien and Viagra) and its side effects (weight gain, hives, headaches, sweating, impaired memory and sexual function). And then there's the time he was so immobilized he thought he'd had a stroke, and the time he tried to contract HIV by having unprotected sex with male strangers--not to die of AIDS, but to have a reason to kill himself.

Solomon's decision to put himself into his book--unlike Burton, he's never offstage long--may put off some readers. Me, I don't get why it's not OK for writers to open up about their own lives, and why reference to personal experience should undercut their credibility. (Hmm. Is this the place to say I pop 10mg of Paxil a day myself?) God knows Solomon's done his homework, and then some. He's traveled to Greenland, Thailand and Africa to check out indigenous styles of depression, visited mental hospitals, talked to the obligatory experts with the obligatory conflicting points of view, poked around in history and done extensive interviews with real people--"the men and women whose battles are the primary subject of this book"--who tell stories both more awful and more uplifting than his own. "The quest for the nonindividual, generic human being is the blight of popular psychology books," Solomon writes. "By seeing how many kinds of resilience and strength and imagination are to be found, one can appreciate not only the horror of depression, but also the complexity of human vitality." So why sit on the story you know best?

This "Atlas of Depression" maps out every imaginable corner of the subject: theories of depression's evolutionary function, its possible causes and treatments, its complex relationships with addiction and suicide, poverty and politics, and how it's been seen by pre-Socratic Greeks and postmodern Frenchmen. Solomon carefully unpacks the subject of "chemical imbalance": on the one hand, "depression is a biochemical matter," but on the other, it "is not the consequence of a reduced level of anything we can measure." Any thought or feeling, he notes, changes brain chemistry--and untreated depression has been found to produce physical lesions on the brain. So is depression a spiritual or a chemical condition? For Solomon, this is a meaningless question. "We do not really know what causes depression," he writes. "We do not really know what constitutes depression. We do not really know why certain treatments may be effective for depression." Meanwhile, his loving family and friends and his dozen pills a day seem to do the trick. More or less. Sometimes.

The stories of the depressed people Solomon has met range from the grimly inspirational (a woman who's cut herself so often her skin will no longer knit, but who still has the greatness of soul to worry about his sadness) to the downright grim. One man in a Pennsylvania hospital remains wretched after drugs and electroshock, has tried to kill himself again and again, but because he has cerebral palsy and is confined to a wheelchair, he's a sitting duck for those who want to save him. He's tried starving himself; when he passes out they feed him intravenously. But the most disturbing and heartening story in this book is that of Solomon's own mother's suicide. Dying of cancer, she held out as long as she could, then swallowed Seconal with her family around her. "I'm sad to be going," she told them. "But... I have loved completely and I have been completely loved..." Her death touched off Solomon's depression, but her life seems to have helped him make sense of it. "To be creatures who love," he writes, "we must be creatures who can despair at what we lose." As one of Samuel Beckett's characters cries, "You're on earth, there's no cure for that!" But Solomon has found some palliatives. Not the least of which is the book itself: 500-odd smart, lucid and sometimes intensely moving pages, written by a man who once couldn't get up the will to turn over in bed.