Machine Language for the Commodore 64, 128, and Other Commodore Computers, Revised & Expanded Edition

This is a good book for someone interested in learning C64 (etc.) assembly language. If you want to actually write anything interesting, you'll need additional reference material (a ROM disassembly like What's really inside the Commodore 64, Fourth Edition is handy if you want to make use of built-in routines from BASIC, for example), but for getting you from zero to 'hello, world', this will do nicely.