Comic books, comics, graphic novels, or whatever you call them are not a genre, they're a medium. Wolk emphasizes this from the outset of this vivid examination of the form and many of the geniuses and misfits of the American mainstream and avante-garde. Always frank, always insightful, Wolk, a former comic book store clerk, covers a lot of ground: pregnant moments, metacomics, parallel Earths, disposable Sunday strips, and, of course, how the world of comics can be "annoyingly male." The first half of the book tackles history along with an overall assessment of what comics mean and how to read them. There are great bits about what makes a "superreader" and how the form blossomed despite the economics of limited shelf space. The second half is a series of precise essays on specific artists, including Chris Ware, Alison Bechdel, Art Spiegelman, Charles Burns and Steve Ditko.