BY the time he died in 1977, expiring at the age of 60 in the back seat of a taxi on his way into New York City from Kennedy Airport, Robert Lowell had turned himself inside out in literature. Socially well connected and classically educated, with the bearing and voice of a disheveled senator, the highborn Bostonian wasn’t well and hadn’t been for years, but despite an exhausting life of marital blowups, manic-depressive breakdowns, political controversy and punishing hard work, he’d managed to invent along the way what came to be known as confessional poetry, a sort of orderly bleeding onto the page that in Lowell’s case combined erudition, anguish and mundane detail for an effect of aching, lurid uplift. The poems of his later, most distinctive period, which began with the publication of ”Life Studies” in 1959, inspired a long dominant mode whose best-known practitioners included two of his students, Anne Sexton and Sylvia Plath. Lowell’s poems proved that if writing is a form of therapy, it’s a uniquely unsuccessful one, at least in medical terms, and that insights into the larger human predicament don’t guarantee their author a good night’s sleep, a stable marriage or a dignified passing. Winning Pulitzer Prizes and the like is no balm either. Nothing (even lithium, it seemed) could halt Lowell’s slide into miserable ill health and psychological chaos.