Synthesized answer
The key concept is "bottom-up programming," which involves solving a programming problem by first building a specialized programming language on top of Lisp itself [1]. This problem-specific language allows programmers to discuss the programming problem more easily [1].
This is achieved using Lisp's basic constructs called "macros" [1]. The book "On Lisp" is known for its detailed explanation of Common Lisp macros and their applications, but it also explores other facets of bottom-up programming within Common Lisp [1].
Synthesized from the book passages below. Chat with the book on Feynman for follow-up.
From the book
Title: On LISP by Paul Graham Description: The title itself, "On Lisp", is a reference to the idea that you can solve a programming problem by first building a programming language that lets you talk about your programming problem easier. In Lisp the programmer builds this problem specific language on top of Lisp itself using basic Lisp constructs called "macros". This style of programming is called "bottom-up programming". On Lisp is especially known for the complete description of Common Lisp macros and their uses, but the book also covers many other aspects of bottom-up programming in…