Billions and Billions
Billions and Billions: Thoughts on Life and Death at the Brink of the Millennium is the last book written by Carl Sagan and published posthumously. It's a collection of essays throughout Sagan's career including one detailing his diagnosis of myelodysplasia. Some of the essays were co-written by his wife and long-time collaborator, Ann Druyan.
I loved the book. Each of the essays was thought provoking, motivating, and compelling. Sagan had a wonderful knack for making complicated topics more comfortable and creating reasonable cogent arguments.