The author, a rabbi, does something ambitious & interesting with Jewish prayer. Instead of the usual classical breakdown of prayer into four types - praise, thanksgiving, repentance, & petition - which also applies to most Christian thought about prayer as far as I know - he attempt something different. He identifies six "archetypes" of the kinds of people who pray, & shows how different prayers in the siddur correspond to what those archetypes need or use. These six archetypes are: the Performer, the Mystic, the Scribe, the Priest, the Meditator, & the "Celebrity-Monotheist." I don't think he completely succeeded in this goal (at least, for me), but I admire the attempt & I did learn some ideas from this book.