Mills & Boon Monographs and Technical Library
Mills & Boon Monographs and Technical Library are short works on advanced technical engineering subjects published in the early 1970s by Mills & Boon, a British publisher better known for its romances. The monographs are in series, for example: Mechanics Engineering Monographs, Mechanics Engineering Library and Electrical Engineering Monographs.
Source: Wikipedia — Mills & Boon Monographs and Technical Library (CC BY-SA 4.0)