The culmination of more than fifty years of research by the foremost living expert on plant classification, is an important contribution to the field of plant taxonomy. In the last decade, the system of classifying plants has been thoroughly revised. Instead of describing every individual family, Takhtajan includes descriptions in keys to families, which he calls \"descriptive keys.\" The advantage of descriptive keys is that they give both the characteristic features of the families and their differences. The delimitation of families and orders drastically differs from the one accepted by the Englerian school and from the one accepted in Arthur Cronquist´s system. Takhtajan favors the smaller, more natural families and orders, which are more coherent and better-defined, where characters are easily grasped, and which are more suitable for information retrieval and phylogenetic studies, including cladistic analysis (because it reduces polymorphic codings).