I may have something older at home. At work right now my oldest, and among my oldest overall hardcopy books about computers anyway, is Introduction to IBM System/360 Assembler Language Programming by Barry J. Passen from 1973.

Edit:
It turns out I do have at least one older volume at home. That is Compiler Construction for Digital Computers by David Gries. It's from 1971 and published by John Wiley.