The international conférence on the Origin of Granites and Related Rocks held in Clermont-Ferrand from September 20th to September 25th 1999 is the fourth in the Hutton Symposium Series. This Series began with a meeting in Edinburgh in 1987 to celebrate the bicentenary of the work of James Hutton, and continued with the second conference held in Canberra, Australia, in 1991, and the third conference held in College Park, Maryland, U.S.A., in 1995.

The objectives of the Hutton Symposium Series are to further our understanding of the origins of granites and related rocks through quadrennial interdisciplinary meetings that involve field trips, oral and poster presentations of scientific results, and informal discussions in the various subdisciplines of the geosciences that impinge upon granites.

In this Abstract Volume, six themes are clearly identified. These themes put forward the main geological problems and not the disciplinary approaches or the tools. Authors of the abstracts generally favour multi-method approaches, combining field, petrological, structural, geophysical and geochemical data together with analogous and/or numerical experiments and modelling. Many contributions give insights on the diverse geochemical and physical mechanisms involved in the genesis, evolution, emplacement and cooling of granitoids.

Two themes are especially relevant to the organization of the Hutton Symposium in France: "Enclaves and magma mixing" and "Granitoids in the Hercynian orogenic belt" (granitoids visited during the pre-and post conferences excursions). The other themes identify the topics most currently debated in the study of granites and related rocks. The theme "Origin, segregation and ascent of granitic melts" is followed by those on "Granites : fabrics, rheology and emplacement" and "Granites and metallogenesis". The theme "Granite petrogenenesis and geodynamic settings" contains contributions dedicated to changes of petrogenetic mechanisms with time, at the scales of either a single orogenic event or global planetary evolution. In some themes, the genesis and emplacement of felsic magmas and granitoids are extended to other planets.