In 2006, Morse issued "Cover to Cover", a collection of cover versions by Mike Portnoy, Randy George and him, recorded during the production of "?", "One" and "Testimony", proving that despite the new focus of his solo career Morse wasn't averse to tackling songs with non-religious themes. In early 2007, Morse released "Sola Scriptura", a concept album detailing the life and struggles of the German theologian Martin Luther, and corruption within the medieval Church. Portnoy and George once again teamed with Morse and were joined by Paul Gilbert (of Racer X and Mr. Big) who contributed a few solo parts.