This is an Orthodox Christian anthology, largely taken from the Philokalia, on prayer. It includes sections from St. Theophan the Recluse, St. Ignaty Brianchininnov, and others. Highly recommended, although more for Orthodox than non-Orthodox.
The Orthodox Church by Timothy (now Bishop Kallistos) Ware is probably one of the best introductions to the Orthdox faith available in book form. It is helpful whether you are an Orthodox Christian looking to learn more about your own faith (me), a new convert, or someone who doesn't know anything a...