On Track comprises 5 pieces for fixed ensembles and 8 pieces for flexible ensembles, with extended notes by the composers to aid the preparation of the music. Each copy comes complete with a CD-Rom containing parts for all the pieces with transpositions for any instrument. These parts come with a licence for printing as many copies as needed, directly from the CD-Rom. A separate 'audio' CD also contains recordings of every piece.

The editor of the compilation, Sadie Harrison, comments:

"Playing in an ensemble with one's peers is perhaps the most rewarding and satisfying thing to do as a young performer, and it is crucial to nurture this element of GCSE courses to reflect this. On Track is a fantastic collection of many different styles, approaches and sounds. There is something in here for everybody, at whatever level, and on whatever instrument. This is what GCSE Music teachers are crying out for, and finally here is something that really hits the mark."

Harrison's comments are echoed by recent examiners' reports from Edexcel, one of the largest examiners of GCSE music. They describe how the music they heard in examinations demonstrated 'an extreme range of standards and revealed evidence of the very wide range of instruments in use'. The AQA (Assessment and Qualification Alliance) Examiners' report in 2004 warns schools against allowing their students to present solo music with a piano accompaniment played by a teacher or with a CD accompaniment for the ensemble performance component. It continues, saying that "it is of utmost importance that the chosen ensemble allows the candidate to show rapport with the other player(s). This is a significant requirement with which many [examination] centres did NOT comply."