If you need to write C extension for Python then this is the place for you.

The full documentation is on Read the Docs.

Code examples and documentation source are on GitHub. The example and test code is available on PyPi.

Links are to Read the Docs.

1. Introduction
2. A Simple Example
3. PyObjects and Reference Counting
4. Containers and Reference Counts
5. Struct Sequence Objects (a namedtuple in C)
6. Exception Raising
7. A Pythonic Coding Pattern for C Functions
8. Parsing Python Arguments
9. Creating New Types
10. Setting and Getting Module Globals
11. Logging and Frames
12. File Paths and Files
13. Subclassing and Using super()
14. Capsules
15. Iterators and Generators
16. Context Managers
17. Pickling C Extension Types
18. Watchers [Python 3.12+]
19. Setting Compiler Flags
20. Debugging
21. Memory Leaks
22. Thread Safety
23. Source Code Layout
24. Using C++ With CPython Code
25. Miscellaneous
26. Installation
27. Further Reading
28. TODO
29. History
30. Index

• Source is on GitHub.
• Documentation on Read the Docs.
• Project is on PyPi.

I have presented some of this, well mostly the chapter "PyObjects and Reference Counting", at Python conferences so if you prefer videos they are here:

• PyCon UK 2015
• PyCon US 2016