ThisvolumecontainsthepaperspresentedatIJCAR2008, the4thInternational Joint Conference on Automated Reasoning, held August 12-15, 2008, in S- ney (Australia). The IJCAR conference series is aimed at unifying the di?erent research principles within automated reasoning. IJCAR 2008 was the fusion of several major international events: -CADE: The International Conference on Automated Deduction -FroCoS: The Symposium on Frontiers of Combining Systems -FTP:...