Research on fossil decapod crustaceans has accelerated since the publication of the Treatise on Invertebrate Paleontology dealing with the group. Increase in the number of paleontologists studying the Decapoda, exploration of previously poorly known areas, and major advances in neontological research has made it possible to transform fossil decapods from the category of interesting and beautiful fossils to that of useful subjects for research in paleoecology and paleobiogeography. Classification of fossil decapods has become more refined as new taxa have been recognized in the fossil record and as neontological approaches to classification, including larval anatomy, comparative spermatology, morphology of novel structures, and molecular analysis, are considered in conjunction with fossil evidence. This combination of approaches can now be used to develop testable hypotheses regarding phylogeny of the group. Detailed observational data on living and fossil biotic associations has been coupled with experimental studies to enhance our understanding of organic interactions as well as to understand the biasing factors of taphonomy that affect the fossil record of organisms with organic exoskeletons. Broad studies of distribution of decapods in time and space are now possible, owing to the increase in number of fossil sites studied and taxa described. We can define patterns of biogeographic distribution that can be tested against patterns derived from the study of more commonly preserved organisms, such as the mollusks. As this research continues, it is anticipated that studies of paleobiogeography and paleoecology will increasingly rely on data from the fossil record of the decapod Crustacea.