Compared to other arthropods, crustaceans are characterized by an unparalleled disparity of body plans. Traditionally, the specialization of arthropod segments and appendages into distinct body regions has served as a convenient basis for higher classification; however, many relationships within the phylum Arthropoda still remain controversial. Can Crustacea even be considered a monophyletic group? If so, then which are their closest relatives within the Arthropoda? The answers to questions such as these will play a key role in understanding patterns and processes in arthropod evolution, including the disappearance of certain body plans from the fossil record, as well as incidences of transition from aquatic to terrestrial environments. Crustacea and Arthropod Relationships, written by a team of internationally recognized experts, presents a wide variety of viewpoints, while offering an up-to-date summary of recent progress across several disciplines. With rich detail and vibrancy, it addresses the evolution and phylogenetic relationships of the Arthropoda based upon molecular, developmental, morphological, and paleontological evidence. Volume 16 is the first in the series to not be exclusively dedicated to discussions specific to crustaceans. While it is still crustaceo-centric, the focus of this volume has been extended to include other groups of arthropods along with the Crustacea. This wider focus offers challenging opportunities to evaluate higher-level relationships within the Arthropoda from a carcinologic perspective. This volume is dedicated to the career of Frederick R. Schram, the founding editor of CrustaceanIssues in 1983, in recognition of his many stimulating and wide-ranging contributions to the evolutionary biology of arthropods in general, and of crustaceans in particular.