Is Baryon Number Conserved?

We suggest that baryon-number conservation may not be absolute and that an integrally charged quark may disintegrate into two leptons and an antilepton with a coupling strength G _Bm_p²≲ 10⁻⁹. On the other hand, if quarks are much heavier than low–lying hadrons, the decay of a three-quark system like the proton is highly forbidden (proton lifetime ≳ 10²⁸ y). Motivation for these ideas appears to arise within a unified theory of hadrons and leptons and their gauge interactions. We emphasize the consequences of such a possibility for real quark searches.