The Frugal Millionaires is a short book which based on interviews by author Jeff Lehman with 70 "frugal" millionaires conducted with the objective of identifying characteristics and habits which millionaires have in common. The material is neatly organised under headings such as investing, savings, health and other topics. The content is presented in the form of a short introduction to each topic followed by a series of short quotes from the anonymous interviewees supplemented by definitions of key terms and some additional remarks by the author.
While I did not get anything new out of the material presented, it would be a useful read for people who think of the typical millionaire as a flashy, high spending super consumer (the reality is that they usually are not). That said, The Millionaire Next Door provides a more detailed and comprehensive coverage of much the same material with considerable additional analysis and (IMHO) is much the better book.