Dr. William Lane Craig is one of the foremost Christian philosophers alive today.  He is known for the Kalaam argument and work on the defense of the resurrection.  His ministry, Reasonable Faith, publishes articles, podcasts and other apologetic resources, and he speaks and participates in debates around the world.

Each semester, he teaches a one week special topic at HBU.  The first class I took with him was on apologetic arguments and covered his book On Guard.  The book covers a range of arguments, such as the cosmological argument, the problem of evil, and the exclusivity of the Christian faith.

If you are looking for a short primer on apologetics and the different arguments for the existence of God, this book would be a good place to start.

On Guard:
on Amazon