This study investigates and compares the skills, knowledge, and activities engaged in as a principal and an assistant principal and their relationship to the preparation of an aspiring middle school principal. Since little information exists, it is possible that no similar investigations have been previously completed. This study also compares the perceptions of principals with the expectations of school districts as to the required skills, knowledge, and activities of principals and assistant principals as delineated in their job descriptions. This study includes a survey of 104 middle school principals who were systematically selected from 1,228 active, public, non-charter, junior high/intermediate/middle schools in California. Surveys were mailed during the last week in October, 2006 and were postmarked for return between October 31 and December 20, 2006. A field test among ten selected principals was completed to establish the validity of the instrument, improve questions, format, and/or rating scales. Positivistic Educational Administration Theory provides the conceptual framework that informs this quantitative study. The study is cross-sectional, utilizing a self-administered questionnaire. Responses were gathered and averaged by category. Since the survey includes Likert scales, factor analysis was used as the statistical procedure to validate the questionnaire. The data provided by this study should be of interest to aspiring administrators, middle school principals and assistant principals, school district administrators, higher education professors of educational administration and other administrator preparation programs.