Merrill Frederick Unger, author of Demons in the World Today, earned his A.B and Ph.D. degrees at Dallas Theological Seminary. He held pastorates in New York, Texas, and Maryland. He taught at Gordon College and Gordon Divinity School, and from 1948 to 1967 he was professor of Old Testament Studies at Dallas Theological Seminary.
I've read three commentaries on Zechariah and many study bible notes, but this is by far the best. No other commentary so effectively blends a historical, cultural, theological, and exegetical perspective in its analysis of this apocalypse of the Old Testament. It is incredibly concise and accessible to bible scholars and laymen alike. It should be considered essential reading for any serious scholar of the bible.