John Alec Entwistle, bassist for the British rock band The Who, died yesterday of an apparent heart attack at the Hard Rock Hotel and Casino in Las Vegas, just one day before a planned US tour. Mr. Entwistle was 57 years old.

Though an autopsy is scheduled for later today, as no official cause of death has been determined, Clark County Coroner Ron Flud did say "we are not investigating this as a criminal case." There were no signs of drugs or alcohol in his room.

Arguably the most influential bass player in rock and roll, Mr. Entwistle was born on October 9, 1944 in the London suburb of Chiswick. At age 15, he and fellow schoolmate and guitarist Pete Townshend connected to start their first band together, The Confederates in 1959.

Soon after, in 1962, Mr. Entwistle was asked by guitarist/vocalist Roger Daltry to enroll in his band at the time, The Detours, and Pete Townshend soon followed. When drummer Keith Moon was added to the mix in 1964, they first became know as The Who, though for a 4 month period of that year they changed their name to The High Numbers. Mr. Entwistle recorded solo as well as with The Who as early as 1971 and continued to perform with John Entwistle’s Ox and Rigor Mortis after The Who officially disbanded in 1983.

Playing what they called “Maximum R and B,” rock and roll derivative of blues and soul, Mr. Entwistle was the eye of the hurricane that was The Who on stage. While Keith Moon assaulted his drum kit, occasionally bashing it into a shambles, Pete Townshend flailed away at his guitar, often smashing it to pieces at a performance’s conclusion and Roger Daltry strutted and whirled his microphone on its cable tether like an airplane propeller, Mr. Entwistle stood quietly at stage left. Amid the onstage chaos of one of the most influential British Invasion bands of the Sixties, Mr. Entwistle was the anchor, known for some of the most complex and audible bass guitar work of the rock genre.

His most notable contributions to The Who’s long list of standards include such favorites as “Boris the Spider” and “My Wife.”