This textbook officially releases tomorrow:

Andreas J. Köstenberger, Benjamin L. Merkle, and Robert L. Plummer. Going Deeper with New Testament Greek: An Intermediate Study of the Grammar and Syntax of the New Testament. Nashville: Broadman & Holman, 2016.

My endorsement:

This grammar’s level of detail falls somewhere between Dan Wallace’s lengthy grammar (1996) and his abridgment (2000). That is a happy medium for Greek professors who teach intermediate Greek in just one semester. It is student-friendly, and it is up-to-date on Greek verbal aspect theory and argument diagrams. Highly recommended!

The three authors introduce their book in this 3.5 minute video:

Rob Plummer introduces the book in this 5-minute video:

Fred Zaspel interviews the authors.