This chapter describes the biology of living brachiopods. The Brachiopoda are significant components of the early Cambrian marine Faunas and are therefore one of the few phyla to be represented of the Phanerozoic era, which extends from the first widespread appearance of organisms with mineralized skeletons until modern times. The objective of chapter review is to chronicle some of the important biological work conducted over the past 25 years and to present an overview of current trends in brachiopod biology. Moreover, many of the recent studies of living brachiopods owe their motivation to a desire to improve palaeontological interpretation of the group. The scaling patterns of brachiopod tissue and other components in relation to total size and their morphological architecture show significant differences from the bivalves and may impose important constraints. Moreover, a general impression of many living articulate brachiopods is of a relatively small organism, in terms of organic tissues, inhabiting a relatively large space, defined by the shell. Brachiopods approximate spherical shapes, as much as their growth patterns and articulation systems allow. This chapter concludes that the brachiopod biomineralization system is ideally suited for the investigation of the interaction between the organic and the inorganic phases during shell growth.