This is the original FASA version of the House Steiner source book. While it appears dated, when compared to more recent versions; the information is still relevant and well worth reading.
Battletech has over the years grown into not just a system, but a whole universe. This book allows players, particularly those playing Mechwarrior; to gain an insight into the various factions.
The PDF contains a wealth of information on House Steiner, which later became Steiner-Davion; after the joining of the Federated Suns and Lyran Commonwealth; to form FedCom. It also gives detailed information on the people, cultures , military structure and religions of the Lyran Commonwealth, which would be a great source for both player and GM alike.