A first set of links about MetaObject Protocol (theory and different implementations including Lisp, Ruby, Python, etc.)
- Serial Parrot/Cardinal Interview: Episode II
- In-process cross-language object interaction: adapters or navigators?
- Jim Hugunin’s The One True Object: Part1 and Part 2
- MOP Specification
- The Common Lisp Object System MetaObject Protocol
- Seeing Metaclasses Clearly
People have recommended also The Art of the Metaobject Protocol by G.Kiczales, but unfortunately I haven’t put my hands on it yet.