Other
Mansfield: Machine Language for Beginners
The classic book on machine language published in 1983 now in digital form.
Other
Mansfield: The Second Book of Machine Language
The second book on machine language by Richard Mansfield published in 1984 now in digital form.
Other
Pc Assembly Language
A down-loadable tutorial for learning the PC Assembly programming language.
Wikimedia
Wikipedia: Assembly Language
A Wikipedia description of the Assembly programming language.
Wikimedia
Wikipedia: Machine Code
A Wikipedia description of machine code (or language), which is the set of instructions executed directly by the computer.