Origins – The Origin of Music 10 is to be found in research conducted by Max Mathews at Bell Laboratories during the years when he worked at the Music IV. Chowning met the researcher at Bell Labs in 1963, they gave him a copy of the source code of its musical software. Chowning took this copy with him at Stanford University. In the last months of 1964 the Music IV was implemented on the IBM 7090 computer of the University. Over the next two years at Stanford continued to use the Music IV for experimental purposes. Many researches were conducted by the same Chowning, including those on sound spatialization and reverberation.
Background history – In 1966 David Poole realized Music 6 for the PDP-6 computer at Stanford. Chowning worked on this project making some functions written in Fortran IV. A few years later, with the replacement of the PDP-6 with PDP-10, John Chowning and James Moorer began to design a new software and completed the Music 10, written in assembler for the PDP-10 computer (hence the name Music 10) and Algol.
References – The software of Chowning and Moorer was completed in 1969, for this reason, in addition to the Music IV, the other reference was the Music V that Max Mathews completed in 1968. By the latter were used several units generating.
Further improvements – Then, through courses and workshops organized between Stanford and Paris, the two researchers continued to work to improve the Music 10, up to prepare the final version in 1975. In particular, Chowning was interested in integrating breakthroughs in the field of psychoacoustics. Moreover, much of the research conducted by Chowning, such as those on spatialization and Frequency Modulation synthesis (FM) were implemented in the Music 10.
Score – After completing the first version of Music 10, as both Chowning and Moorer collaborated on a software utility designed for the Music 10 score. It was Score, a software developed by Leland Smith in 1972. In fact it was a useful software to manage the score of other Music N, such as the Music IV and Music V.
Besides the United States – In 1973, Chowning moves to Ircam in Paris. Here brings with him the Music 10, after taht the Music V was already introduced. The center, conducted by Pierre Boulez, made extensive use of two Music N software, both for research and for the composition of musical works.
For this topic I’ve read.
 AA.VV., The Cambridge Companion to Electronic Music, Cambridge University Press, New York, 2007.  John Chowning, Personal Communication, 2009.  Peter Mannig, Electronic and Computer Music, Oxford University Press, New York, 1985.