Craig Keener’s Bible Background Commentary has sold over half a million copies. It was first published in 1993 and has been of great assistance to students and pastors for a quick reference to the background issues at stake in a certain passage. What’s the deal with head coverings? Baptism for the dead? Who are the Epicureans? What was Ephesus like, and what is the Temple of Artemis? These are questions that you could certainly Wikipedia in a jam, but why not allow a seasoned scholar who focuses on NT background explain it for you? And he does it in one not-so-large volume!