c. 150-160 this is the most prominent Gospel harmony by an early Christian apologist and ascetic.

This particular "New edition and formatting, Based on Public Domain Text of Roberts-Donaldson Elngish Translation" copyright 2009 by Cliff Lee.

The Introduction is straight out of wikipedia so the link should get you to any changes regarding this material.

This helps round out my selected study material for 2012 emphasis on knowing God through knowing Jesus. At a later date I'll link the other books to this entry for a complete picture.