Epworth Sleepiness Scale: test to indicate how poorly you’re sleeping. This is one of the first things a sleep doc will ask you to fill out. Pre-CPAP I scored “9 – Seek the advice of a sleep specialist without delay.”
The Promise of Sleep by William C. Dement. This is the first book I ever read on sleeping disorders, and it’s invaluable. Covers Sleep Apnea, DSPS, ASPS, Insomnia, etc. He goes over the symptoms, the diagnosis process, and the available treatments, in addtion to providing a brief and entertaining history of the field of sleep science. I’m sad to see that the book is out of print, but there do seem to be some used copies floating around.