Also, importantly, the language really predates the notion that software itself might be a business, and certainly the notion that a programming language by itself would need or want to be sold separately. So the fact that it would not sell well was not exactly relevant. And what with free software and all, you can't much sell languages any more anyway, so it's come full circle and this is a strange time for anyone to have started complaining about how a language is packaged for sale.

And anyway, the subject line presupposes that Lisp has not caught on. This is like saying that astrophysics or calculus or brain surgery has not caught on because in relative numbers, there might be more people doing other things. The success of Lisp is not measured in the number of people using it, it's measured in the utility to those people who do use it. Turning it into C (or C++ or C#) to make it more popular would not be success. In the world's menu of computer language options, we don't need them all to be Taco Bell.

Kent Pitman on comp.lang.lisp

Guy Lewis Steele Jr. & Gerald Jay Sussman, The Art of the Interpreter or, The Modularity Complex (1978)

Guy Lewis Steele jr. & Gerald Jay Sussman, The Art of the Interpreter or, The Modularity Complex (1978)

The PageRank algorithm.

From Hastie, Tibshirani and Friedman's The Elements of Statistical Learning (2009)

George Polya, Mathematical Discovery: On Understanding, Learning and Teaching Problem Solving (1962)

George Polya, Mathematical Discovery: On Understanding, Learning and Teaching Problem Solving (1962)

Felleisen, Findler et.al, How to Design Programs (2018)

Preface to Felleisen, Findler et.al, How to Design Programs (2018)

This book does teach how to have recursive thinking as your second nature, without even directly talking about recursion per se.

Friedman & Felleisen, The Little Schemer (1987)