Michael your doubt (which is quite understandable) is precisely the reason that you wouldn't want to consciously activate a book if you wish to make use of direct learning. The conscious mind can be quite a sabotager of results because of its negative conditioning, etc.
I believe that direct learning will work. Almost every self-improvement book or course stresses the importance of setting a goal, and visualizing its attainment regularly. ‘Think and Grow Rich’ suggests that you put a card in your wallet with your top 3 goals(or so) and look at it regularly. Hang your goals on the mirror. Post them anywhere that you will see them regularly.
The key is to not worry about how you will achieve the goal. Concentrate more on 'why' you want it. Reasons come first and then the 'how' will reveal itself. First you become what it is that you want in your mind and then your subconscious mind will become your ally in striving to achieve those objectives. The subconscious mind will say something like 'hey this guy is an expert golfer we better start finding ways to manifest this'.
Anyone that has tried to kick a habit knows how difficult it is to quit when the subconscious mind is an enemy. If your self-image is that you are a smoker then guess what it is going to be difficult to willpower your way out of that habit. Your brain doesn't want to make you into a liar. It believes that it is addicted--so it is.
The cool thing is that the subconscious mind doesn't know the difference between vivid imagination and reality. That's why recording the tape that is suggested in the Natural Brilliance book is so important. Use it everyday. It will change your self-image from a person that can't achieve the skill or goal to an expert at it. After that occurs your mind is going to fight like crazy to make your new successful self-image come true.