Includes: 'Languages' (possibly an outline for work to be done for the projected book) 'Algol 60' (on verso, 'Language O') 'L-PAL' 'A purely applicative language' 'Commands or expressions' 'Simple programming language with side effects'.

Duplicated typescript of a paper read by Scott and Strachey (on Language O and Language 1) at Princeton.

Sequences of notes and routines (collaborative work with Scott). Includes: 'A small "Continuation" language' (typescript note, basis of the work) 'Program Segments', calculations and narrative, 2 items both April 1970 'Jumps, Hops, Labels', more extended sequence of calculations and narrative, April 1970 'Commands/Jumps Semantics' …

Two manuscript drafts for a work, perhaps a lecture, with this title.

Notes and examples of symbols for computer languages, in various type-faces, in connection with planning and publication of P.R.G. Technical Monographs, 1970-1971. Includes letter to Scott on the subject, March 1970.

Bundles of notes, calculations and narrative, various dates March 1969-February 1972, with headings or titles as follows: 'Basic Functions' 'Conditional Expressions' 'Simple language without side effects' 'Sample Class 2 language (derived from PA)' 'Abstract syntax' 'Stored Commands' 'Lists and Polyadic…

Undated notes and calculations by Strachey on formal semantics.

Notes and ideas by R. Milne, S. Linfoot and other members of the P.R.G.

Tagged set of 'Miscellaneous Formulae' in Strachey's hand, various dates March 1970-March 1971.

'Useful formulae and equivalences' (by C. Wadsworth, annotated by Strachey). Miscellaneous problem sheets, etc. by D. Park, J. Stoy and others.

Includes a paper by D. Park, and miscellaneous notes by Strachey.

Includes extended narrative by Strachey 'λ-Calculus as a language. Contains details of proof of correctness of substitution lemmas etc. in the model', December 1970. Six bundles of notes and calculations by Strachey, R. Milne, C. Wadsworth.

Miscellaneous bundles of notes and routines, all in Strachey's hand, some dated December 1970-January 1971, on the design and implementation of the 'Stream Compiler' which was a new compiler for BCPL to run on the P.R.G.'s Modular One System. The work was being done by one of Strachey's D.Phil. students (Alan C. Bamford) under his direction. (Information supplied by M. Harper of P.R.G.)

Printout headed 'Russian Problem', December 1971. (Program for the 'Stream Compiler'). Also included are printouts for a 'Factorial' program and of part of the 'Stream Compiler' itself, and other notes and printouts 1972-1973.

Strachey's original specification for an 'Off-Line Job Queue' for the P.R.G.'s Modular One computer, dated 28 May 1971. This program served as a 'batch processor' for programs held in a queue. [A version of the program was still in use (January 1978).] (Information supplied by M. Harper of P.R.G.)

Plans, chapter headings and notes for book A Mathematical Theory of Computation, to be written by Scott and Strachey. The plan and chapter headings are in Scott's hand; comments, notes and drafts for sections of the work are by Strachey. Various dates August 1969. The book was not completed, but many of the notes and calculations in the following folders were preparatory material for the project.

Notes and ideas on types of languages, some by Scott but mainly by Strachey. Includes: 'Language 0' 'Language 1' 'Mini-language 1', February-March 1970 'Language 2. Assignment and Hops' 'Language 3. The simple procedure language', by Scott and Strachey.

'Paradigm Programming Language (P.P.L.). Version 1' (by Scott and Strachey). 'P.P.L. Version 2' (by Scott and Strachey).