Charmless Hadronic B Decays at BaBar

Using 22.7M B{bar B} events collected with the BABAR detector at SLAC, we present preliminary measurements of the branching fractions for charmless hadronic decays of B mesons into two-body, quasi two-body and three-body final states with pions, kaons, and {rho} and a{sub 0} resonances. In the search for exclusive B{sup 0} {yields} {pi}{sup +}{pi}{sup -}{pi}{sup 0}, we measure {Beta}(B{sup 0} {yields} {rho}{sup {+-}}(770){pi}{sup {-+}}) = (28.9 {+-} 5.4 {+-} 4.3) x 10{sup -6}, together with the relative asymmetry {Alpha}{sub phys} = -0.04 {+-} 0.18 {+-} 0.02. We also set the upper limits on B{sup 0} {yields} {rho}{sup 0}(770){pi}{sup 0}, non-resonant B{sup 0} {yields} {pi}{sup +}{pi}{sup -}{pi}{sup 0}, B{sup 0} {yields} a{sub 0}{sup {+-}}({yields} {eta}{pi}{sup {+-}}){pi}{sup {-+}} and B{sup 0} {yields} K{sup 0}{bar K}{sup 0}.