This is an excellent resource for reading the Four Gospels in a chronological harmony, especially while comparing the King James Version to the Inspired Version (the Joseph Smith Translation). I believe that the authors based their work on the Thomas M. Mumford harmony, as the Gospel Harmony is very similar - which is a good thing. Like my copy of the Mumford work, my copy of this one is slowly getting notated, cross-reference, and underlined.
Excellent resource for studying the gospels, lays out the text side by side, the index helps you find specific passages. The JST is a really nice addition. Invaluable preparation aid for teaching the New Testament.