officers were instructed to place these posters in conspicuous places and a sufficient number of these posters was reproduced to permit a change of display once every two weeks. _Another aspect of the "security-consciousness" program was the utilization in the forward area of short movie briefs which were shown from time-to-time at all theaters just prior to the evening feature. These movies were produced by Lookout Mountain Laboratory and the U. S. Naval Photographic Center and each depicted a senior Task Force member giving a short talk on individual responsibility for security. Another special movie was produced in the forward area in which the CJTF re-emphasized security precautions and this' was shown once at each theater and on each ship just prior to the first of the shot series. In addition to these films, a second group of ten, produced by Lookout Mountain Laboratory in the ZI, was designed for more frequent showing and was devoted to depicting various ways in which an individual might inadvertently cause a breach of security. A last group of films, also produced by Look- out Mountain Laboratory in the ZI, dealt with questions and answers similar to those included in the examinations on Security Memoranda Numbers 2 and 3. Perhaps the single most difficult security problem to occur during CASTLE was the recurrent one of "Q" clearances. The time interval between submission of initial papers on an individwl and the conclusion of the necessary investigation prior to granting clearance was such that personnel would oftentimes arrive at their 16