Wigley has probably written one of the most concise and straight forward explanations and commentaries on Revelation that I've ever read. He doesn't take verse by verse necessarily and doesn't get into theories or all the possibilities that may exist for each symbol, sign, or happening. Instead, Wigley divides the book up into topical categories as he goes from start to finish. He provides great explanations from the Old Testament for his own determinations as to what certain things mean. It's easy to understand and it would make sense to any reader. I'll definitely be using his study as a resource for future writings and sermons.
I'd highly recommend this book for anyone interested in Revelation and desiring a straight forward approach to understanding it.