I can recommend https://realpython.com/products/cpython-internals-book/ https://realpython.com/products/cpython-internals-book/ as a decent initial documentatio

I can recommend https://realpython.com/products/cpython-internals-book/ https://realpython.com/products/cpython-internals-book/ as a decent initial documentation of cpython. I have a copy of this book at my desk for the few cases when I need to debug GIL or memory allocator related issues in cpython.