These books were published in the middle of the 1980s, and contained a story written around some simple-to-moderate complexity BASIC program that the user entered, interacted with, and in some cases debugged to make work properly as part of the story. It had #1 and #2 from their original prints way back when, but it took me years to get the remaining 8 books. They generally had a decent enough action-adventure-cliffhanger type story, so they were always a fun read.