"Beneath Apple DOS" by Don Worth and Pieter Lechner was my bible back then. Reading this book absolutely blew my mind and opened up a world of possibilities, no

"Beneath Apple DOS" by Don Worth and Pieter Lechner was my bible back then. Reading this book absolutely blew my mind and opened up a world of possibilities, not mentioning a much more intimate knowledge of how copy protection worked on the Apple ][.