The Year of Magical Thinking by Joan Didion
This one has been on my list for years simply because Joan Didion is so celebrated and this is her most personal collection of essays. Focused on the year after her husband dies and in which her only daughter fights death in hospital beds, Didion not only shares her own experience with grief but she shares psychological research on grief. It's clear that Didion shared a great love with her husband, John Gregory Dunne, and this memoir was probably written as therapy--they had been married for 40 years. This book is best suited to those who have experienced such grief and trauma, but will most likely prove powerful to other readers, too.