The Middle Jurassic Series, comprising the Aalenian, Bajocian, Bathonian and Callovian stages, represents some 20 million years of Earth history. In Britain, it comprises a complex succession of sedimentary rocks ranging from fully marine carbonates and mudstones, to brackish and non-marine mudstones and sandstones. These lithologies reflect a variety of depositional environments including shallow marine, saltmarsh, coastal lagoonal, deltaic and fluvial. A classic ammonite-based chromostratigraphy is available in parts of the marine succession but elsewhere, the ammonites fail and the biostratigraphical control is more speculative. Describes over 100 Middle Jurassic sites, from the Dorset coast to the islands of the Inner Hebrides off north-west Scotland. Together they provide a complete spectrum of the British Middle Jurassic succession. Arranged geographically, the site descriptions are divided between five chapters (Wessex, Cotswolds, East Midlands, North Yorkshire and Scotland), each of which has an introductory section placing the sites in context. The volume thereby provides an up-to-date review of the Middle Jurassic stratigraphy of Britain, calling on the extensive literature of over 150 years but also including previously unpublished data.