One might ask;

        "How many other synoptic mergers have there been that combine and harmonize the texts of
the New Testament Gospel accounts?"

Since at least Tatian’s Diatessaron of 160 CE, the four familiar Gospels of the New Testament have been read together; either as a harmony in columns side-by-side; and as a merger, where the individual words of the parallel verses are combined or unified in some way.

Tatian, a Syrian student of Justin Martyr, created his merger Diatessaron, meaning "out of/from/through" "four", by adding material from the Gospels of Matthew, Mark and Luke, to the Gospel of John.  In those many places where the verses from the four Gospels parallel each other, Tatian basically chose one set of verses from one Gospel over the other(s).  Despite its editorial shortcomings, being a more complete account than reading even any two of the Gospel accounts separately, the Diatessaron was widely read throughout the early church, and used exclusively as the Gospel by the eastern and Coptic churches for more than 200 years, until 405 CE when the Roman church produced the Vulgate version of the New Testament in Latin.  The Vulgate opened with the same four Gospel stories of the life of Jesus that Tatian had used, except once again as four separate and overlapping accounts.

Since Tatian, there have been many harmonies, and a few mergers of the words of the three more closely related "synoptic" Gospels, and also a couple of works that include the text of the Gospel of John.  Learning from past examples, and using a precise notation, this book goes beyond all previous mergers and harmonies by splitting the parallel verses into individual words, which can be aligned on a word-for-word and thought-for-thought basis.

In the end, with each and every word from each of the four Gospel accounts of the New Testament included or accounted for, Five Column: The Synoptic Gospel is the most complete and accurate word-for-word merged harmonization of the texts of the four Gospels of the New Testament that has yet been produced.