| February 28, 1957 | Hats | L. Ron Hubbard writes HCOPL "Hats". | |
| January 13, 1959 | HCO Area Secretary Hat Material | L. Ron Hubbard writes HCOPL 'HCO Area Secretary Hat Material'. | |
| January 29, 1959 | HCO Communicator Hat | L. Ron Hubbard writes HCOPL 'HCO Communicator Hat'. | |
| May 5, 1959 | Policy on SECEDs and Hats | L. Ron Hubbard writes HCOPL 'Policy on SECEDs and Hats'. | |
| June 16, 1959 | Hat of PE HCO WW | L. Ron Hubbard writes HCOPL 'Hat of PE HCO WW'. | |
| September 15, 1959 | Hats and Other Folders | L. Ron Hubbard writes HCOPL 'Hats and Other Folders'. | |
| October 5, 1959 | Tape and Record Production Hat | L. Ron Hubbard writes HCOPL 'Tape and Record Production Hat'. | |
| March 31, 1961 | The Director of Processing's Case Checking Hat | L. Ron Hubbard writes HCOPL 'The Director of Processing's Case Checking Hat'. | |
| June 9, 1961 | Technical Hat Checking, Vital Policy for HCO Area Sec | L. Ron Hubbard writes HCOPL 'Technical Hat Checking, Vital Policy for HCO Area Sec'. | |
| April 6, 1962 | Technical Director Basic Hat | L. Ron Hubbard writes HCOPL 'Technical Director Basic Hat'. | |
| May 15, 1963 | Instructor Hats | L. Ron Hubbard writes HCOPL 'Instructor Hats'. | |
| April 6, 1965 | Letter Reg Hat | L. Ron Hubbard writes HCOPL 'Letter Reg Hat'. | |
| July 1, 1965 | Hats, the Reason For | L. Ron Hubbard writes HCOPL 'Hats, the Reason For'. | |
| July 1, 1965 | Hats, the Reason For | L. Ron Hubbard writes HCOPL 'Hats, the Reason For'. | |
| January 7, 1966 | Leaving Post, Writing Your Hat | L. Ron Hubbard writes HCOPL 'Leaving Post, Writing Your Hat'. | |
| January 7, 1966 | Leaving Post, Writing Your Hat | L. Ron Hubbard writes HCOPL 'Leaving Post, Writing Your Hat'. | |
| May 8, 1966 | LRH Communicator, No Other Hats | L. Ron Hubbard writes HCOPL 'LRHCommunicator, No Other Hats'. | |
| May 10, 1967 | Bookstore Officer Hat | L. Ron Hubbard writes HCOPL 'Bookstore Officer Hat'. | |
| July 2, 1967 | Hatting and the Environment | L. Ron Hubbard writes HCOPL 'Hatting and the Environment'. | |
| February 5, 1969 | Double Hats | L. Ron Hubbard writes HCOPL 'Double Hats'. | |
| April 20, 1969 | Hats, Not Wearing | L. Ron Hubbard writes HCOPL 'Hats, Not Wearing'. | |
| April 9, 1970 | Conference Hats | L. Ron Hubbard writes HCOPL 'Conference Hats '. | |
| April 25, 1970 | More on Lines and Hats | L. Ron Hubbard writes HCOPL 'More on Lines and Hats '. | |
| May 14, 1970 | Hat Checkout Sequence | L. Ron Hubbard writes HCOPL 'Hat Checkout Sequence '. | |
| July 14, 1970 | Hats, Basic and False | L. Ron Hubbard writes HCOPL 'Hats, Basic and False '. | |
