Concept albums have been a staple of rock music for decades, going all the way back to iconic albums like Sgt. Pepper’s and Tommy. While jazz musicians have also attempted to build recordings around a central theme, it is a much more difficult proposition when dealing with instrumental music because there are no words to tell a story. This challenge has not deterred guitarist Julian Lage, whose latest album, Gladwell, is the named after a fictional town`around which the songs are based.