Fosdick was unknown to me until I picked up this book. The 4 stars is because the copy I have, at least, could use a good re-edit for spelling errors.
But the subject matter and the author's approach to so many aspects of prayer are worth the time of anyone who wants maturity in this area of their lives, their walk with the Savior.
Did I always see his point or agree on the premise? Not every time - usually, yes. But the scriptural references to prayer, his insight and own maturity, and the thoughts his lessons provoked in my own mind, were good food for the soul.
If the reader is only interested in prayer for the purpose of approaching God when he or she wants some personal gratification, you will be rebuked. That is only a starting point - for infants. Fosdick was interested in promoting growing intimacy with our Lord because of prayer, and praying ever more correctly and effectively because of that greater closeness. It can be a wonderful cycle.