Non-fiction books about people with extreme obsessions or lifestyles (like Michael Finkel’s The Stranger in the Woods or The Art Thief)

I couldn’t put the 2 books above down and am seeking more books about people who are extreme in their obsessions or lifestyles. Another aspect I really enjoyed was the relevant background research detailed the books, letting me learn about random subjects (e.g. solitude or art history). TIA

by smoothegg