A chance encounter; The first meeting: Simon describes the basic mechanism of the nebular theory -- The second meeting: Steven describes the basic mechanisms of the capture theory -- The third meeting: Simon is questioned about angular momentum and planetary orbits -- The fourth meeting: Simon describes planet-planetesimal interactions and Steven explains how initial capture-theory orbits are modified -- The fifth meeting: Steven and Simon talk about the proportion of stars with planets -- The sixth meeting: Steven and Simon discuss spin-orbit misalignment -- The seventh meeting: Steven explains the formation of terrestrial planets and the Earth-moon relationship by the capture theory and then Simon covers the same ground with the nebular-theory interpretation -- The eighth meeting: Simon and Steven talk about satellite formation -- The ninth meeting: Simon describes the Nice model -- The tenth meeting:Steven describes the formation of asteroids and comets and the origin of many other features of the solar system -- The eleventh meeting: Steven describes the origin of isotopic anomalies in meteorites -- The twelth meeting: Simon and Steven summarize the two theories