Here is a selection of books which seem to be most helpful for seekers.
Those marked with a * are the easiest to read.
The Orthodox Church by Bishop Kallistos (Timothy Ware) ‑ the best single introduction to the history and life of the Church.
*The Orthodox Handbook by Father Thomas Hopko ‑ four volumes: Doctrine, Spirituality, Worship, and Bible and Church History.
*Becoming Orthodox by Father Peter Gilquist. Story of the pilgrimage of a large group of former evangelical Protestants to Orthodoxy.
For the Life of the World and Of Water and the Spirit by Father Alexander Schmemann ‑ a completely different perspective on worship and sacraments from what is usually heard in Western Churches.
The Church is One by Alexey Khomiakov ‑ this short nineteenth-century essay is a classic assertion of the Orthodox understanding of the Church as mystery of grace versus juridical rationalistic simplifications. Can be read online at http://www.fatheralexander.org/booklets/english/church_is_one_e.htm
*Steps of Transformation by Fr. Meletios Webber - relates the twelve steps of Alcoholics’ Anonymous to the teaching of the Orthodox spiritual fathers. Not just for addicts but for anyone seeking spiritual insight and sanity
The Orthodox Study Bible – Now complete with Old Testament with notes and articles explaining Orthodox use and understanding of the texts.
*The Way of the Ascetics by Tito Colliander ‑ short, simple distillation of the teaching of the Fathers on prayer and spiritual struggle.
*Father Arseny, life of a priest whose love and faith shone in the Soviet prison camps.
*Pearl of Great Price by Sergei Hackel – life of St. Maria Skobtsova, an Orthodox nun who helped Jews in Paris during World War II and died in a Nazi concentration camp.
*The Ascetic of Love by the Nun Gavrilia – life of mother Gavrilia, a remarkable Greek nun who traveled the world as an unmercenary healer
*The Holy Fire by Robert Payne - lives and passages from nine Church fathers from the second through the fourteenth centuries, vividly told with imagination and context
Christian writings of the first few centuries, especially St. Ignatius of Antioch, St. Polycarp, *St. Justin Martyr, and the *Didache. There are several collections of these now published, such as The Apostolic Fathers, edited by Jack Sparks. Fourth century writers such as St. Athanasius, St. Basil, St. Gregory the Theologian (of Nazianzen), *St. John Chrysostom. Several collections of writings of the *Desert Fathers of Egypt are available which give a sense of the Orthodox approach to prayer. Many of these can be read online, for example at http://www.ccel.org/fathers.html
Many of these books are available in our bookstore, or can be ordered from St. Tikhon's Bookstore, South Canaan, PA 18459 (http://www.stots.edu/), St. Vladimir's Bookstore, 575 Scarsdale Rd., Crestwood, NY 10707, www.svots.edu), Concilliar Press http://www.conciliarpress.com/, Box 76, Ben Lomond, CA 95005 and many other places.
Again magazine, published quarterly by Concilliar Press http://www.conciliarpress.com/, Box 76, Ben Lomond, CA 95005 - excellent teaching magazine, especially for those of Protestant background.
The article on "Eastern Orthodoxy" by the late Fr. John Meyendorf in the current edition of the Encyclopedia Britannica is excellent.
A lot of the spirit of Orthodoxy is conveyed in the writings of Dostoevsky, especially Crime and Punishment, The Idiot, The Demons, The Brothers Karamazov. The recent translations by Pevear and Volokhonsky render all others superceded
There is a lot of Orthodox material on the Internet, which varies a great deal in accuracy and quality. Some good places to start are http://www.oca.org,/ http://www.antiochian.org, and http://www.goarch.org and http://fatherstephen.wordpress.com/