In this interview Robert Cahn discusses his tenure and support of the Supernova Cosmology Project (SCP) as director (1991-1996) of the physics division at Lawrence Berkeley Laboratory (LBL). Reviews of the SCP. Saul Perlmutter as building a new field of research in distant supernovae. Astrophysics in Berkeley. Style of research in the physics division at LBL. On discoveries as gradual and the importance of statistics and systematics. Pentaquark discovery as an example of error. Physical Review's policy of what constitute 'evidence' (three Sigma) and what constitutes a 'discovery' (five Sigma). Historical example of the discovery of the neutron. Historical example of the discovery of the Psi particle. Two milestones in the discovery of positive Lambda: the first distant supernova and then, finding batches of supernovae. Use of the Hubble Space Telescope by High-z team and SCP. Controversy heated because of the possibility of winning the Nobel prize.