Reddit mentions of Gonzo

No, it's "Gonzo," which is a sort of photo-biography of Thompson's life. It's got hundreds of pictures of him and ones that he took himself, and it's pretty great. If you aren't picky about cover quality, you can get it for very cheap.

Gonzo is a word used sometimes in reference to the muppets, but, amongst adult company, is much more commonly used in reference to cult personality and writing sensation Hunter S. Thomson, who described his style of drugged out immersion reportage as 'Gonzo Journalism.'

The image on the front of the book is the 'gonzo fist,' a two-thumbed, four-fingered, peyote-grasping badge he used as a symbol during a run for sheriff, but has since come to represent his career as a whole.

That specific book is probably this one.

Hope that helps!