Very odd. My copy is complete, so if you can't otherwise locate the missing content, I could scan those page for you. They cover: i) multiple simultanous linear equations with unknowns (the problem the ABC was created for), ii) ordinary differential equations such as ballistics calculations (ditto, the ENIAC), iii) partial differential equations, such as fluid dynamics, although the example he uses is from quantum mechanics. You could contact the seller and ask them to check, specifically. Well, it say what it means: it's a first edition - some collectors prefer them; and it doesn't have all the stickers, glued-in paperwork, internal markings etc that one finds in a library copy. Collectors often find that annoying - I tend to stay away from ex-library copies unless there's a huge price difference. Oh, goodness, there's a long list. I'll put up an annotated bibliography on the Computer History wiki. They are: Charles J. Bashe, Lyle R. Johnson, John H. Palmer, Emerson W. Pugh, "IBM's Early Computers", MIT Press, Cambridge, 1986 Emerson W. Pugh, Lyle R. Johnson, John H. Palmer, "IBM's 360 and Early 370 Systems", MIT Press, Cambridge, 1991 Both are excellent, as are: Emerson W. Pugh, "Memories That Shaped an Industry: Decisions Leading to IBM System/360", MIT Press, Cambridge, 1984 Maurice V. Wilkes, "Memoirs of a Computer Pioneer", MIT Press, Cambridge, 1985 the perspectiv of IBM). Noel