Recently, the role of the olivocerebellar projection in cerebellar operation has drawn the attention of many scientists who are trying to understand how the cerebellum controls movements. The papers published in this book were presented at a meeting held in Turin on August 9-12, 1987 as a satellite symposium of the 2nd World IBRO Congress in Budapest. It was planned in collaboration with Rodolfo Llinas and Masao Ito, although the latter was not able to attend. Some of the papers are in the form of reviews, others are short communications of new unpublished results. All aspects of research on the inferior olive are covered including morphology, neurotransmission, development, and electrophysiology, as well as its relation to behaviour and to human pathology. The lively, endless scientific discussions have not been published, but the reader may well imagine them from the different and sometimes contrasting pOints of views expressed in the papers. There are many examples showing that integrity of the inferior olive is necessary for some forms of motor learning and for the adaptive capabilities ofthe motor system. On the other hand, there is evidence that the inferior olive is important in controlling the dynamic characteristics of movement, both as a phasic and as a tonic operator. From this, two main viewpoints have emerged. The plasticitists attribute the role of inducing plastic changes to the synapse between the climbing fibre and the Purkinje cell.