In November 1990 the Handel Institute held its first Triennial Conference, whose subject, `Handel Collections and their History', reflects the great importance for Handel scholarship of the many collections of manuscript copies of his works. These collections provide fascinating insights into the compositional history and chronology of his works and their later modification for performance or for subsequent revival; much too can be learnt about Handel's working methods. The conference papers, given by an international panel of distinguished Handel scholars, are presented here.