This chapter looks at the outset that the history of the rise of "up-or-out" tenure to the status of now standard practice is mostly a blank spot in our understanding of modern. The first codification of "up-or-out" tenure was born of a decision Conant made in the spring of 1936, when he quietly took it upon himself to change existing procedures governing reappointment and promotion of junior members of Harvard's Faculty of Arts and Science. As a matter of official policy, the meaning of tenure in relation to FAS appointments changed in at least two ways. The first might be described as a simple but telling change in usage. Prior to the adoption of the Second Report, the concept of tenure at Harvard had not been associated either with a single, carefully circumscribed probationary period or with strict enforcement of an "up-or-out" decision rule.