[ Cambridge, MA ]: Massachusetts Institute of Technology 1931. First Edition. 447-488 pages. Stapled wrappers. Tan wrappers printed in a fugitive red ink. Dampstaining upper left corner throughout. Red stain to spine area mostly front panel. Vol 67, No 55, Pub. Serial No. 865: Publications from the Massachusetts Institute of Technology. Contribution from the Department of Electrical Engineering, Serial No. 75, October 1931. A "List of contributions from the Department of Electrical Engineering" is printed in red on inside covers. Very Good. Cloth. 
Vannevar Bush's "'The Differential Analyzer. A New Machine for Solving Differential Equations" contains 21 figures, including 9 photographs of portions of the differential analyzer. The paper describes this new machine for the solution of ordinary differential equations, first place in service at the Massachusetts Institute of Technology (MIT). The article details the general philosophy behind the device, the mechanical challenges, methods of placing an equation on the machine, and methods used by the device.
Vannevar Bush was MIT's first Vice President and Dean of Engineering from 1932-1939. While at MIT he invented the differential analyzer, an analog device that was the most powerful computing machine prior to the electronic digital computer...The differential analyzer proved so useful that copies were built at the University of Pennsylvania, the General Electric Plant in Schenectady, New York, and the Ballistics Research Laboratory at Aberdeen Proving Ground...' (see Origins of Cyberspace 244).
This paper was first published in the Journal of the Franklin Institute (Vol 212, No. 4, October 1931), and was no doubt available as an author's offprint from that publication. We aren't entirely sure where this pamphlet sits in the publishing timeline. It clearly states it was reprinted from the Journal of the Franklin Institute, and was probably used (much like the Bell System Monograph series was) for MIT to publicize the work of their best scientists. We're pricing this as a period reprint, but not as an offprint which would be significantly more desirable.