A prospective buyer of Allegre's new book on Isotope Geology will immediately want to know if it might supplant the classic and long-time favorite of the similar title by Gunter Faure. While similar in coverage, many recent advances are only to be found in Allegre's more recent book. Importantly, Allegre's book utilizes a novel and very effective use of "worked problems" ... an extremely useful pedagogical approach. This textbook will be useful for a wide audience, from undergraduate generalists, to graduate students learning the nitty gritty tools of the trade, to senior practitioners such as myself who need a refresher in some forgotten arenas.