BSP is a freeware map creation program written by Yahn Bernier for id software's game, Quake, and games using the Quake engine. The name of the program refers to the binary space partitioning data structure commonly used by such games and the .bsp file format used by Quake for compiled maps.
BSP was originally written using an old version of Borland C++ and released in the latter half of 1996, when Quake was still fairly recent.
The last official release made by Yahn was 0.93b on 02/12/1998. Mr. Bernier was subsequently hired by Valve Software to work on their game, Half-Life and the Worldcraft editor (as it was then called), and BSP was abandoned.
The (broken) source code was given to a BSP user early in 2000, but it was set aside due to the effort involved in getting it back into a working state, and nearly forgotten.
In July 2006, BSP 0.94b was released. It has been ported to the Win32 API, adding several new features and fixing a number of problems in the code in the process. The current version is 0.96d, released 10/10/2007.