His Excellency, the Most Reverend Metropolitan Kallistos of Diokleia (also known by his lay name, Timothy Ware) is a titular metropolitan of the Ecumenical Patriarchate in Great Britain. From 1966-2001, he was Spalding Lecturer of Eastern Orthodox Studies at Oxford University, and has authored numerous books and articles pertaining to the Orthodox Christian faith.
A very balanced, informative, and helpful look at the Eastern Orthodox view of salvation. This was recommended to me as a "small book of careful statements," which is a perfect description. I'd recommend this to anyone wanting to better understand the Orthodox understanding of sin, human nature, grace, etc.