Albeit that the question is a little unclear as mentioned, I can still hopefully offer some thoughts for the heart of what you asked:
How do you bridge the gap between giving a person a book and letting them make the most of it >and giving a person a book with the expectation that it will do some good?
Christian writing today is not the same as the Bible, in many ways. However, that is not to say that it is not inspired by God. Luke 12:11-12 reminds us that the spirit speaks through us to encourage and spur on one another.
11 “When you are brought before synagogues, rulers and authorities, do not worry about how >you will defend yourselves or what you will say, 12 for the Holy Spirit will teach you at >that time what you should say.”
However, the God's message has been already revealed in its complete fullness through the Bible. Christian writing today is useful for explaining, analysing and promulgating the gospel message, but not for adding to it. For this reason, books have their limits. For this reason, we can't hold the expectation that through reading books, a person will be made aware of their shortcomings.
My belief is that the frame of mind when giving someone a book should be that it will aid them in their understanding and reading of the scripture- a kind of 'Cliff's Notes' on the bible, and that through this reading, they won't be swayed by the powerful writing or deep arguments, but by the power of God working through the Holy Spirit.
In summary, when giving someone a book, you do it not as an act to hope that they will 'make the most of it', but that it will help them in their understanding of the only book that saves, the Bible. (As with everything, praying also helps).