BX is built upon Libbitcoin library (C++) , a set of cross platform C++ libraries for building bitcoin applications. If you are a Java programming, consider bitcoinj, a library for working with the Bitcoin protocol. If you're familiar with Python, python-bitcoinlib is a Python2/3 library which provides an easy interface to access the bitcoin data structures. Use this library to manipulate the internals of how Bitcoin works. Similarily, BitcoinLib is a .Net Bitcoin & Altcoins Library & RPC Wrapper in C#.
This is a companion discussion topic for the original entry at http://www.bitcoin-en.com/learn-blockchain-programming.html