Anybody hear of this book of music? I just happened to come across this online. Seriously? Dvorak with a book of jazz music? What is the music like?

Probably unlistenable?

Keep in mind that during his short stint in the US, Dvorak became a very influential teacher of musicians who went on to instruct some of the most progressive musicians of the next generation. Dvorak's students were big influences on Aaron Copland and Duke Ellington, because Dvorak would take Jews and African Americans as students, unlike most other composition instructors.

Hello,
this is probably not Antonin Dvorak, but Milan Dvorak and his music is quite nice. He wrote two books of Jazz Etudes. Yes, they are both available on-line, just google for "milan dvorak jazz piano studies I" and "milan dvorak jazz piano studies II" and you should find them.
Have fun with them, I'm pure beginner working on book I's Etude 5... :-)
Karel