Chuck Berry, who died Saturday at 90, was one of the architects of rock'n'roll as a singer, songwriter and guitarist. More than any artist of the '50s, his songs exploded with imagery that saw rock'n'roll not just as a fad but as the future -- a vision of freedom that transcended generation and race. Berry's opening solo on "Johnny B. Goode" blared reveille for subsequent generations of rockers. Every rock guitarist since is in his debt. In addition, Berry wrote and sang at least two dozen rock'n'roll classics, including Maybellene, Roll Over Beethoven, and Back in the U.S.A., many of...