The papers are extensive, relating to almost every aspect of Blackett's career in science and public life. There is biographical and personal material including large numbers of letters of congratulation received on the occasion of the various scientific and public awards and honours with which Blackett's achievements were recognised. There are records of his work on particle disintegration, cosmic rays, astrophysics and magnetism in the form of laboratory notebooks, working papers, correspondence, lectures, publications and broadcasts. There is documentation of his activities on various defence projects and as a member of government committees before, during and after the Second World War. Blackett's political interests are represented by material relating to the Association of Scientific Workers, Labour Party discussion groups on science and technology policy and the Ministry of Technology instituted after the Party's 1964 electoral victory. There are records of a wide range of science-related interests such as the history of science and technology, science, education and government, and nuclear weapons and disarmament, and of his overseas activities including material relating specifically to India and that concerned with matters more generally affecting developing countries.

A few lacunae in the surviving material have been identified. There are no documents relative to Blackett's service with the National Research and Development Corporation or the Department of Scientific and Industrial Research and, of his correspondence during the Second World War, only that for 1942 survives.