Valuable for many reasons, among them:

• Its account of Mill's early education. Mill was at first homeschooled, by his father; he began learning Greek when he was three and Latin at eight. Training in the classical languages wasn't unusual and hadn't been even in Shakespeare's time, but training at such an early age pretty certainly was.

• Mill's discussion of how, at age 20, he fell into what we now call depression (Mill terms it a "dry heavy dejection") and of how he got out of it. Suffice it to say that his escape looks like a kind of cognitive therapy, an alteration in his habits of thought, which Mill worked out for himself.

• The dual view it gives. This edition's preface (written in 1924) says, "In many ways [Mill's Autobiography] is primarily an account of the social history of England in the first three quarters of the Nineteenth Century." More properly, because we now take social history to mean something else, it involves philosophy, public affairs such as education, the practice of politics, and political journalism. But the story is presented by way of Mill's active and restless engagement in those matters. As the preface goes on to say, "One sees an age, and one sees a man."

• Its illustration of 19th-century prose style and even punctuation (this edition follows a manuscript in Mill's own hand).

I read the Autobiography the first time during undergraduate school or soon after, I think because I had become interested in Mill's thought (though this book was hardly the best way to learn it in any depth). I read it the second time as part of my studies for a play on suicide. Mill never mentions suicide, but the crisis of purpose that he endured can lead in that direction, and the method of his escape can be what keeps one alive.