Three-page typescript letter, 4 April 1968, from M. Richards at M.I.T., giving reasons for his decision not to write a CPL compiler in BCPL, but rather to improve the 'efficiency and machine independence' of the BCPL compiler. 'I realized that the reasons for using CPLOCODE as the intermediate object code are not valid if BCPL is implemented for its own sake. I have thus chosen to specify and implement an alternative object code which is specifically designed for BCPL'. A printout of an example of its use was enclosed with the letter and remains in the folder. Also included is a photocopy of 'Compilation of Demo BCPL. Not debugged', 5 May 1968, sent by Richards and annotated by Strachey.

The letter also describes the arguments employed by Richards in a paper he was writing on 'rationalizing my views of types'.