powerful open-source Lisp implementations are a dime a dozen, why not try JMurmel instead?
The language is inspired by Common Lisp, except it's a Lisp-1, and it is mostly a subset of CLtL-1.
Jmurmel can be used standalone with or without the Repl, for "#!"-style hashbang scripts or embedded in a Java program.
It features [documentation for the core language](https://jmurmel.github.io/murmel-langref.html) as well as [documentation for the default library](https://jmurmel.github.io/mlib.html), a REPL, an interpreter, a compiler, macros, backquotes, [turtle-](https://jmurmel.github.io/img/fern-min.png) and (simple) [bitmap graphics](https://jmurmel.github.io/img/julia-min.png).
It is implemented in Java (compatible with Java8..22-ea) with some library functions and macros implemented in itself.
Code is on [Github](https://github.com/mayerrobert/jmurmel), the latest release with a precompiled jar (or alternatively a Windows .exe-style launcher) is at [Release V 1.4.5](https://github.com/mayerrobert/jmurmel/releases/tag/jmurmel-...).
A Repl example:
JMurmel> ((lambda (x) (list x (list (quote quote) x))) (quote (lambda (x) (list x (list (quote quote) x)))))
==> ((lambda (x) (list x (list (quote quote) x))) (quote (lambda (x) (list x (list (quote quote) x)))))
JMurmel>