Besides two keynote papers by Stefano Ceri and Michael Kifer, the book contains revised full versions of 28 papers selected from a total of 88 submissions.The volume gives a highly competent state-of-the-art report on DOOD research and advanced applications. This book constitutes the refereed proceedings of the 4th International Conference on Deductive and Object-Oriented Databases, DOOD '95, held in Singapore in December 1995.