Tangible Math in J by K E Iverson - an example of how to use J as a mathematical laboratory for experiment with suggested functions and with any functions you care to specify. [36pp 8 pounds]
Introduction to J by K E Iverson - an introduction to J with hints about how to learn to use it and examples for you to try and vary. [47pp 8 pounds - included with J when you buy from I-APL]
Programming in J by K E Iverson - an extended introduction to J with many more examples and covering a much wider selection of functions. [75pp ten pounds]
Arthmetic by K E Iverson - selected topics in arithmetic; see the review in Vector by Professor Smillie. [118pp twelve pounds]
