The Noonday Demon: an Atlas of Depression / Andrew Solomon 571 p.

This was published in 2001 and a National Book Award Winner, but I've only just read it, having loved Solomon's 2012 Far from the Tree.  This was also excellent, examining depression and its many sub-topics - addiction, suicide, treatment, poverty, politics and others, through the lenses of Solomon's own experience with serious illness as well as those of several others whom he came to know well over years of research.  What's so great about this author is that he amasses an enormous amount of scholarship (and more important, understanding) and then assembles it into a narrative that's both personal and comprehensible.  It's daring, too: he reveals some fairly dark things about himself, but these disclosures are illustrative rather than feeling attention-seeking.  I'm looking forward to whatever he does next.