I generated a tutorial for Boost.Contract upon request from a potential user:
Boost.Contract: A Complete Tutorial and Instruction Manual
https://github.com/cpphelp/tutorials/blob/main/boost-contract-tutorial.md
and in Chilean Spanish:
Boost.Contract: Tutorial Completo y Manual de Instrucciones
https://github.com/cpphelp/tutorials/blob/main/boost-contract-tutorial-es.md