This review describes the early beginnings of X-ray diffrac-tion work on muscle structure and the contraction mech-anismin the MRC Unit in the Cavendish Laboratory, Cambridge, and later work in the MRC Molecular Biology Laboratory in Hills Road, Cambridge, where the author worked for many years, and elsewhere. The work has depended heavily on instrumentation development, for which the MRC laboratory had made excellent provision. The search for ever higher X-ray intensity for time-resolved studies led to the development of synchrotron radiation as an exceptionally powerful X-ray source
