Scientology Chronology - April 1957
| April 1, 1957 | Always Register and Invoice | |
| April 1, 1957 | Learning Rate (Part 2) | |
| April 1, 1957 | Technical and Administrative Divisions | |
| April 5, 1957 | Proportionate Pay Plan Proposal | |
| April 6, 1957 | Central Files and Procurement | |
| April 8, 1957 | Advisory Committee | |
| April 8, 1957 | Group Auditing | |
| April 9, 1957 | Dismissals and Post Changes | |
| April 9, 1957 | Employing and Discharging of Personnel | |
| April 9, 1957 | Grievances | |
| April 9, 1957 | Bulletin Board | |
| April 9, 1957 | Communication Center | |
| April 9, 1957 | List of "Purposes" | |
| April 10, 1957 | Morale Note | |
| April 10, 1957 | Student Intensives | |
| April 10, 1957 | "The HPA/HCA Full Course..." | |
| April 12, 1957 | Control Processes | |
| April 12, 1957 | Control, Communication and Havingness, Part I | |
| April 12, 1957 | Control, Communication and Havingness, Part II | |
| April 13, 1957 | Group Processing: Emphasis on Control | |
| April 13, 1957 | Group Processing: Emphasis on Control (cont.) | |
| April 13, 1957 | Radiation and Scientology | |
| April 13, 1957 | Radiation and the Scientologist | |
| April 13, 1957 | Radiation in War | |
| April 14, 1957 | Scientology and Children | |
| April 14, 1957 | The Organization and the Field | |
| April 14, 1957 | The Reality Scale and the Effect Scale | |
| April 15, 1957 | The Control of Hysteria | |
| April 18, 1957 | Auditor's Training Evening, CCHs | |
| April 19, 1957 | Now that the Proportionate... | |
| April 21, 1957 | Income | |
| April 21, 1957 | Information Boards | |
| April 23, 1957 | "HCO Is Now Handling..." | |
| April 28, 1957 | HCO Board of Review, Goal | |
| April 30, 1957 | Issue Authority for Mimeo | |
| May 1, 1957 | Eyesight and Glasses | |
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