Book excerpt: Renowned Berklee College of Music faculty guitarist Jon Finn, combines his experience, education, and stylistic versatility in this eclectic series of lessons for aspiring rock guitarists. Jon's innovative approach is unique, fun, and challenging. The book/audio set and video both offer a well researched original take on the use of pentatonic scales in rock improvisation. Using his "Warp Refraction Principle" which takes into account the major third tuning interval between the second and third strings, Jon presents a series of five vertical patterns applied in two-string increments throughout the fretboard. The philosophy behind this project is to present concepts and techniques as a thought process rather than simply providing a reference manual. Includes access to online audio and video.