What an insight!
The title, "Buddhism Plain and Simple," serves a-perhaps unintended-double meaning. First the content of the book itself is, for such a difficult subject to the 'western' mind, simplifying to the nature of Buddhism. In most of the so-called western world, Buddhism is another religion a kin to Hinduism and a slew of unnamed cast based worldviews. Hagen skillfully and logically reduces the original concepts preached by the Buddha as a way of seeing the world, a philosophy of sorts, and strips off the many colorful layers of lore and culture acquired through the religion's sweep into Indo-Tibet, thus presenting the most simplified form of Buddhist teaching available. The alternate understanding of the book's title is that Buddhism itself is, by nature, the idea of life as simplicity applied. While this concept may be difficult to grasp (especially for those who have not been raised with eastern philosophy) it is, nonetheless, simple. Get it?
Anyone (really, anyone) desiring to gain an applicable understanding of "Buddhist philosophy" (for lack of a better term) should start with this book. Take the time to read it carefully, reread it, mull it, and then see how it affects you. The least you can expect to gain from Hagen's work, is a better understanding of the simplicity that life has to offer to those willing to let go.