Ten years have elapsed since the publication in 1978 of Vol. 49 of the Handbook of Experimental Pharmacology [41], a toOO-page survey of the data then available on Ergot Alkaloids and Related Compounds. A booklet published in 1979 presented the in formation on one of these compounds, namely co-dergocrine (Hydergine@), as extracted from the Handbook and updated to take the latest developments into account [42]. Co-dergocrine had at the time been on the market for 30 years and had given rise to over 2000 papers, so that one might have felt justified in thinking that its scientific history had virtually come to an end. It has now become obvious that such a view would have been wide of the mark. Research on the pharmacology and clinical pharmacology of co-dergocrine has remained as active as ever. The resulting obsolescence of the 1979 booklet made necessary the preparation of the present version. Like its predecessor, it is intended as an inventory of findings and facts rather than a work dealing with their interpretation.