Perhaps it's because, like me, people don't know it's out there yet. I just discovered it today while doing my perfunctory browsing of the writing section at Barnes & Noble. Picked it up out of curiosity and didn't put it down...I took it straight to the register instead.
This book is hilarious, reading some of the ways to tell - if you have a file on every member of your family, you fall in love because someone uses a rare word properly, you stop an argument to write down a note, your "uniform" is a ratty bathrobe and slippers and your commute is 20 seconds - 20 extra if you stop to use the bathroom, you want to have WRITTEN but don't want to write, I could go on and on...I was in the store CRACKING THE FVCK UP!!!!!!
Think of Jeff Foxworthy's "You Know You're a Redneck If" and then add the wit of a writer TO a book about writers.
No writer should be without one.