This revision guide is very useful, but it does have a clear error on page 62. Under Tripartite System point three it states that students went to technical schools if they failed the 11+ this is factually incorrect; you had to pass the 11+ to go to either grammar or technical schools. It is apparently going to be corrected in the next printing of the book, however, it does concern me that there may be other errors in the guide. Therefore, useful, but keep a close watch on the facts which you are learning, and, if in doubt, cross check them with another text book.