Robyn Chapman's Drawing Comics Lab is a primer or introduction to drawing comics. The book talks about the different aspects of drawing comics besides just drawing. Those would be stuff like creating characters, understanding panels and pacing, choosing drawing materials, etc.
Many of the lessons revolve around thinking, design and writing, rather than the actual technical part of putting pen on paper. Many have basically brain-storming exercises suggested by guest artists. Those artists' tips are quite useful at kick-starting your brain into coming up with ideas.
The book is really elementary and the 52 labs (lessons) can be brief at times. Even the author also suggested other books that you should check out if you're into those all-in-one books on drawing comics, namely, Making Comics by Scott McCloud, Drawing Words and Writing Pictures by Jessica Abel (this would get my recommendation).