The planktonic foraminifera have, for over forty years, been recognised to be the most valuable stratigraphic indices for marine sediments of Late Cretaceous and Cenozoic age. However, their evolutionary origins in the Jurassic and their development, morphological evolution and systematics in the Early Cretaceous have, until now, been poorly understood. br/ This book illustrates for the first time all the published taxa known from the Jurassic, and clarifies and corrects their taxonomy. br/ The taxonomy and stratigraphic distribution of the Early Cretaceous planktonic foraminifera are also revised, and all of the published species are illustrated, using the type specimens. The systematics of the Early Cretaceous forms are clearly set out, both for species and for genera: their evolution is explained as well as the ecological importance of the morphological changes they have undergone. Moreover, by analogy with the Recent Globigerinacea the palaeoenvironmental significance of these Early Cretaceous taxa is discussed. br/ The book deals with 136 species belonging to 26 genera, five of which - emCompactogerina/em, emHaeuslerina/em (of the Jurassic), emLilliputianelloides/em; emClaviblowiella/em and emPlanohedbergella/em (of the Cretaceous) - are new. Range charts are provided, as are extensive keys for the more important genera. br/ Superbly illustrated, with 65 high-quality plates, this work will be an invaluable reference for all micropalaeontolists and biostratigraphers worldwide, with many species illustrated by SEM for the first time. This is the first book to collate all known information on the early evolutionary origins of the planktonic foraminifera.