This article traces the development of the EMS VCS3 synthesiser from the inception of its precursor, the Don Banks Music Box, through its prototype to its commercial release. The nature of the design team and their technical and aesthetic choices are also discussed. The VCS3 is significant in that it was the first commercial European synthesiser and the team that created it – Tristram Cary, David Cockerell and Peter Zinovieff – were key figures in the development of British electronic music. This detailed study of the genesis of the VCS3 and some of the factors that influenced its design touches on many technical and historiographical strands that may be examined in more depth by future scholars.