RRTCM and Card College are designed to transform you from a neophyte into a competent manipulator by going through steps. Most other magic books (Expert Card Technique included) have a wide variety of information regarding different sleights and methods. These are more instruction manuals, if you will, and they are designed to help you in specific areas or with particular moves. So, it is you that must determine which path to take when studying these manuals. You should read every page, but it is not imperative. Reading the whole book allows you to see different takes on a double lift or the pass that you may not have seen, so it is definitely beneficial to read over everything. You can, however, study more on your specific interests and skim the remaining. Best of luck to you!