We have developed a filter-based framework where several fundamentally di_erent techniques can be combined to provide fully automated and efficient heuristic solutions to veri_cation and possibly other NP-complete problems. Such an integrated methodology is far more robust and efficient than any single existing technique on a wide variety of circuits. Our methodology has been applied to verify the ISCAS 85 benchmark circuits and efficient verification results have been presented on a large set of industrial circuits which could not be verified using several published techniques and commercial verification tools available to us.