Gospel Parallels are books that present the text of the Gospels side-by-side to aid comparison among the evangelists' accounts of similar (or unique) stories in the Gospels. These resources mostly involve the Synoptic gospels, but some include relevant material from the Gospel of John.
Parallels offer the reader the ability to quickly see at a glance how particular pericopes differ between the gospels. By utilizing the insights of source criticism, inferences can be drawn that highlight the particular changes or edits made to the Gospel tradition by individual evangelists, and therefore aid an understanding of authorial intent.