Classics, Both Old and New
Most of these books are in print and can be purchased new. Those out of print can almost always be purchased through a network of used book dealers such as is available from Amazon.com. We expect to add more books; keep watching.
Louis Berkhof, Systematic Theology
Perhaps the best single-volume book on systematic theology.
Alexander Reese, The Approaching Advent of Christ
One of the best critiques of pretribulationism from the standpoint of historical premillenialism.