When You Are Engulfed In Flames and Naked. I really love his essays and can't imagine reading too many of them. So many laugh out loud moments within well-structured and often complex narratives. The situations are often quite fascinating, in a micro way, and his observations can be astute. I love reading about his childhood and family -- particularly his mother, about his years during and after college, and his travels and life with Hugh. I feel like I know him.
I read Let's Explore Diabetes with Owls a couple of years ago, which I think is his most recent collection. I can't wait for the next one.