Pocket Guides?

Mark Ezekiel, Handbook of Anesthesiology

I used this book so much in the OR, I had to retape the spine 3 times. The Boston Mass book is good as well, but for quick references I always (and still do on occasion) relied on Ezekiel. It will fit in your back pocket. That was useful to me.

Some of this will depend on your stage of training and your style of learning.

Ezekiel's is excellent. I've also used Macksey's Nurse Anesthesia Pocket Guide. Some of my classmates use the handbook to Barash's Clinical Anesthesia. Epocrates for your handheld is free and a excellent reference.