This is one of the first volumes to be published in the series of Chapman and Hall Chemistry Sourcebooks which provides carefully tailored information to workers in specialized areas of chemistry. The information contained in this book is derived from the Dictionary of Organometallic Compounds, published in November 1984. The organic compounds of the six metals in this volume are of great interest both to inorganic and organic chemists. Organonickel and organopalladium compounds are frequently used as selective reagents in synthesis and as catalysts for organic reactions. Organoplatinum compounds, however, are generally slower to react and lend themselves to mechanistic studies. A vast range of such compounds has been prepared. Whilst organometallics of the gold triad are fewer, they display a range of interesting structures , and organocopper compounds are widely used synthetic reagents. It is therefore anticipated that this particular compendium will reach a wide readership. The databank on the properties of organometallic compounds, which is represented in its current form by the Dictionary of Organometallic Compounds and its subset publications such as this volume, will be kept continuously up-to-date. Supplements to the main Dictionary will appear annually and revised editions of this Sourcebook will be published from time to time as demands permits. RJ. Cross D.M.P. Mingos VII Introduction 1. Using the Sourcebook (2) Any compound with an established use, such as in catalysis, as a synthetic reagent or starting material.