JOHN WILLIAMS is one of the most versatile and virtuosic guitarists around. He studied the classical repertoire with the master Segovia, wedded that technique to the electric guitar, and, for a time, was a member of the British band Sky. On "Echoes of London," his latest release, he explores both the classical and popular sides of his instrument, while celebrating the city in which he dwells. The result is only half successful.

Side one boasts Williams' crystalline arrangements of crowd-pleasing works by composers ranging from Bach to Purcell to Elgar. Using a dubbing process, five of the eight selections feature Williams accompanying himself. Particularly special are his Baroque-style treatment of folk singer Ralph McTell's wistful ballad "Streets of London," and the rapid, cascading runs of Handel's "Harmonious Blacksmith."

Side two abandons this clear, unfettered approach for a lushly orchestrated sound that leaves Williams in the shadows. Though the songs are certainly appealing -- "A Foggy Day," "A Nightingale Sang in Berkeley Square," -- Steve Gray's arrangements list heavily toward the strings, and Williams' impeccable melodic lines sound thin when juxtaposed against this accompaniment.

JOHN WILLIAMS -- "Echoes of London." CDS42119 digital; appearing Friday at 8:30 p.m. at the Kennedy Center Concert Hall.