A brief history of TrueType
The TrueType digital font format was originally designed by Apple Computer, Inc. It was a means of avoiding per-font royalty payments to the owners of other font technologies, and a solution to some of the technical limitations of Adobe's Type 1 format.
Originally code named "Bass" (because these were scalable fonts and you can scale a fish), and later "Royal", the TrueType format was designed to be efficient in storage and processing, and extensible. It was also built to allow the use of hinting approaches already in use in the font industry as well as the development of new hinting techniques, enabling the easy conversion of already existing fonts to the TrueType format. This degree of flexibility in TrueType's implementation of hinting makes it extremely powerful when designing characters for display on the screen. Microsoft had also been looking for an outline format to solve similar problems, and Apple agreed to license TrueType to Microsoft.
Apple included full TrueType support in its Macintosh operating system, System 7, in May 1991. Its more recent development efforts include TrueType GX, which extends the TrueType format as part of the new graphics architecture QuickDraw GX for the MacOS. TrueType GX includes some Apple-only extensions to the font format, supporting Style Variations and the Line Layout Manager.
Microsoft first included TrueType in Windows 3.1, in April 1992. Soon afterwards, Microsoft began rewriting the TrueType rasterizer to improve its efficiency and performance and remove some bugs (while maintaining compatibility with the earlier version). The new TrueType rasterizer, version 1.5, first shipped in Windows NT 3.1. There have since been some minor revisions, and the version in Windows 95 and NT 3.51 is version 1.66. The new capabilities include enhanced features such as font smoothing (or more technically, grayscale rasterization).
Microsoft's ongoing development effort includes the TrueType Open specification. TrueType Open will work on any Microsoft platform and Apple Macintosh machine, and includes features to allow multi-lingual typesetting and fine typographic control.
The next extension to the TrueType Open format is to be TrueType Open version 2, a collaborative effort with Adobe Systems to produce a format capable of containing both TrueType (and Open) and PostScript data.