This book came to me as a recommended follow to up to J.I. Packer's Knowing God. The first thing you will notice about this book is that it is extremely short. However, don't let that deceive you; it is very rich and almost paragraph gives food for thought.
Reading the biographical details of Tozer's life could lead you towards thinking he had abandoned sound theology for wishful mysticism. There are some traces in the book that caused me to raise my eyebrow where Tozer seemed to advocate an experientialist approach to theology, rather than sola scriptura. However, he states at the start that all experience has to be founded on sound theology. In this respect, it is very much a case for those looking for “solid food” that Paul refers to in 1 Corinthians 3. As such, I would not recommend this to a new christian or to someone who is investigating christianity, as there is much foundational knowledge which is assumed throughout. Were someone to start with Tozer, it would be very easy to get the wrong end of the stick.
But with that cautionary word out of the way, I have to say that this was a joy to read. Clearly written from a passionate heart, Tozer shows us a glimpse of what it means to move from merely knowing about God, to knowing God himself. One of my habits that gets me funny looks from fellow commuters on the train is my habit of underlining quotes in various books. Usually, this is quite rarefied, but in this instance it was more practical to keep my pen in my hand as I was reading than to keep putting it away and bring it back out again.
There is one genuine flaw in it, I believe. In a few instances dotted throughout the book, Tozer seems to adopt a slightly anti-intellectual and anti-science viewpoint, indicating that they are incompatible with christian belief. However, as a christian with a scientific background, I cannot agree with this worldview. A true understanding the power of science can only obtained when you understand its limitations. In my opinion, since God is outside of nature, no naturalistic outlook can ever lead to a complete understanding of God; science is the exploration of creation, working out how God put the cosmos together and how it works. So it is not a case that science is anti-christian, but rather that scientific methodology is (to borrow an analogy from N.T. Wright) like shooting arrows at the sun: it can take aim at God, but it will never hit.
This is a serious book for serious people. It is certainly one that I will be coming back to in the future, and would recommend for anyone wanting a guide in helping them get closer to God.