Preface: IGCP project 426 */Granite Systems and Proterozoic Lithospheric Processes O. Tapani Ra ¨mo ¨ a, , W. Randall Van Schmus b , Jorge S. Bettencourt c a Department of Geology, P.O. Box 64, University of Helsinki, Helsinki 00014, Finland b Department of Geology, University of Kansas, Lawrence, KS 66045, USA c Instituto de Geocie ˆncias, Universidade de Sa ˜o Paulo, Caixa Postal 11348, CEP: 05422-970, Sao Paulo, Brazil Abstract This introductory chapter of the IGCP-426 Special Issue of Precambrian Research presents an overall account of the goals and activities of IGCP-426 (Granite Systems and Proterozoic Lithospheric Processes) in the first 4 years (1998  / 2001) of the project. The thirteen original articles of the issue are based on papers given in the past meetings of IGCP- 426 and are briefly introduced. # 2002 Elsevier Science B.V. All rights reserved. Keywords: Proterozoic; Continental crust; Lithosphere; Isotopic age; Granite 1. Introduction Since 1998, International Geological Correla- tion Programme Project IGCP-426 has been con- ducted to study and coordinate research on Proterozoic granitoid rocks under the theme ‘Correlation of the Petrology and Geochemistry of Proterozoic Granite Systems with their Metal- logeny and Tectonic Environments’, or, in short, ‘Granite Systems and Proterozoic Lithospheric Processes’. The overall goal of the project has been to correlate the petrology, geochemistry, and metallogeny of Proterozoic granitoid rocks with the lithospheric processes that formed them and with the tectonic environments in which they are located. To pursue these goals and to promote international collaboration between scientists working in these fields of geology, the project has arranged several symposia and workshops in North America, South America, and Europe. This special issue of Precambrian Research comprises a selection of thirteen original papers that deal with various themes of the project, and are based on presentations given in IGCP-426 meetings in 1998  /2001. In this introductory article, the aims and activities of the project, that will run till the end of 2003, are described, and the main results of the thirteen papers are reviewed. 2. Aims of IGCP-426 To correlate Proterozoic granitic systems with their tectonic environments and corresponding  Corresponding author. Tel.:  /358-9-19150810; fax:  /358- 9-19150826 E-mail address: tapani.ramo@helsinki.fi (O.T. Ra ¨mo ¨). Precambrian Research 119 (2002) 1  /7 www.elsevier.com/locate/precamres 0301-9268/02/$ - see front matter # 2002 Elsevier Science B.V. All rights reserved. PII:S0301-9268(02)00115-8