Most of the material dates from 1959-1964, when Strachey was in practice as a private consultant; some antedates this period, (see MS. Eng. misc. b. 283/D.82-MS. Eng. misc. b. 283/D.84 for advice requested while Strachey was still teaching at Harrow) and several firms maintained an arrangement, whether on a formal or an ad hoc basis, for several years after the formal winding up of the practice.

Though industrial firms form the major part of those involved, Strachey was also consulted by universities, research establishments and official bodies such as National Research Development Corporation.

The material is presented, in general, alphabetically. It may consist of formal and financial agreements, arrangements for visits and meetings, working notes, research material and reports, and should be read in conjunction with items in the working papers, notes and calculations series relating to e.g. work on E.M.I. and Ferranti computers.