E.M. Bounds' classic book on prayer has been understood for decades to be the source for learning about the effective use of the discipline. One particular subject in the book that I took a liking to was the idea of importunity, defined as troublesomely urgent.
Bounds addresses the issue of importunity this way: “It is not an impulse of energy, not a mere earnestness of soul; it is an inwrought force, a faculty implanted and aroused by the Holy Spirit.”
Bounds suggests that it is impossible to be so forward with God without the power of the Holy Spirit! How many times have we (as Bounds suggests in the same chapter) given up on a prayer after a small period of time? Instead, we ought to be breaking down the doors of heaven and begging time with the Father for as long as it takes, and that type of passion can't happen without the Holy Spirit's leading.
Bounds continues his treatise on importune prayer in the following chapter, suggesting that God surrenders himself only to the “whole-hearted and deeply earnest.” The use of the word surrender is important. It's not that God actually throws up his hands and gives in, but Bounds does suggest that God is a more willing participant in such prayer. This is more easily seen as the reader learns about Bounds' past.
It becomes immensely clear for the reader that Bounds was a man of prayer, and after a small amount of research, even from the simple sources such as Wikipedia, the reader can realize why he become a man of prayer. Returning to the war-ravaged South after the Civil War, Bounds sought to help rebuild, and he did so through lengthy prayer meetings. This fervent, passionate prayer, such as he speaks of in The Necessity of Prayer, is what developed his theology on the topic.
Bounds makes great pains to use Scripture to back up his ideas, or rather he seems to take his ideas straight from Scripture. When speaking of importunity, for example, he uses examples from Elijah, Moses, Daniel, and of course Christ. While it is perfectly fine for a minister to come to his own conclusions, Bounds still understands that his conclusions are best when they reflect the Bible. As to clarity, the only problem with a work this old is that it is naturally harder to read for modern eyes. This is not a mark against neither the writer nor the reader. Aside from this issue, the clarity and writing style are perfectly fine.