This volume had its origin in a workshop held at Park City, Utah, 23-25 May 1984. The objective of the workshop was to provide an opportunity for cloud physicists to assess the status of knowledge and understanding about the physics of precipitation formation in clouds and the response of clouds to glaciogenic seeding. All paperbounds were by invitation. Half of the time was given to discussion and debate sparked by 4 major review paperbounds and 14 short reports. Restriction of the workshop to scientific aspects of glaciogenic seeding for precipitation enhancement was intentional.