Kopal's research notebooks, dating from the mid-1940s when he was engaged on war-work on ballistics. Some of the notebooks were created during his period at MIT, but the majority date from his appointment at Manchester. Subject matter relates primarily to his research on close binary stars and numerical analysis, although there are also notes on artificial satellites and theoretical mathematics connected to general astrophysics; the content of the notebooks is primarily mathematical in nature and because of the highly specialised content, the catalogue does not attempt interpretation of this content.
Some of the notebooks are dated by Kopal, at least the date when the notebook was commenced. The books contain numerous enclosures, usually further mathematical notes, but also copies of publications which he was using. Kopal mainly used computation notebooks acquired at Harvard and MIT, when he continued to use at Manchester, which are paperback volumes containing squared notepaper.