This is the fourth book in the “realm” series of mathematics texts done for Houghton-Mifflin, and the first lacking “realm” in the title. Like the final book in the series, An Easy Introduction to the Slide Rule, Quick and Easy Math has been obsoleted somewhat by the advent of electronic calculators in the early 1970’s, although not nearly as badly. It is not, after all, entirely uncommon to come across a situation where you need to do some quick math and a calculator isn’t handy, whereas it is virtually unheard of for anybody to actually use a slide rule nowadays.