There's a growing body of musicians today who are pursuing what you might call a dual career. One as a member of a group, one as a solo performer.

Perhaps the best example of the trend is Rod Stewart. By day, he's the raspy voiced superstar whose solo albums and whose concerts break all sorts of records. By night, he's lead singer of a group called Faces, a mediocre group kept afloat only by Stewart. Point is, Stewart has two careers.

So does Neil Young. Maybe three, depending on his latest ventures. Between the solo efforts and the group efforts, it's pretty difficult to keep up with his activities.

A lot of other group members are doing the same thing. Jefferson Airplane members keep turning up everywhere. Especially Grace Slick, Paul Kantner and Papa John Creach. Solo, session and group work.

Same goes for some of the Jackson Five, most notably young Michael. And Nicky Hopkins, an honorary member of nearly everyone's group, has also just gone solo.

And that's only the beginning. The number of people – group members launching solo careers — in the studio getting ready is astounding.

It's hard to say exactly why all this is happening. Maybe group members are doing it so they can go in directions the group structure won't permit. Or maybe they're on ego trips and convinced they're better than their group record shows. Or maybe they're just tired of only one-fourth or one-fifth of the bread and hungry for bigger and better things.

Anyway, the latest folk to join this ever growing body are certain members of the Who. Roger Daltry, the group's lead singer, has just released "Daltry." And now John Entwistle has just come out with his solo effort, a little number called "Rigor Mortis Sets In." It's on the Track (distributed by MCA) label.

Remember Entwistle? Probably not, as he is the Who's least memorable member. Not exactly least memorable, more accurately he's the sanest.

At Who concerts, while Roger Daltry would make like the teen baton queen and twirl his mike all over the place, while Peter Townshend would do the living windmill number, swinging his arms and plucking his guitar like a hawk, while Keith Moon would beat, kick, torment and ultimately destroy his drums, John Entwistle would stand off to the side, still and calm, playing his bass and looking on with an air of detachment.

He gave the impression of being a pillar of sanity in a sea of madness. Which made him less than memorable.

Not because of a lack of talent or anything – he's one of the finest bass men around – but because he was not rock theater in the same sense as the rest of the group.

Now that he has a solo album out and isn't buried by the other three group members, you get a chance to sample his talent at close range. Very close range.

And surprise. It's a monster talent. Very accessible, very simple, very nice rock and roll.

That's the key. Rock and roll. As Entwistle sings in "Gimme That Rock and Roll," the song that opens the album: "You can keep your classical music/you can stuff your rhythm and blues/ And you know what you can do with your dixieland too/You can stick it anywhere you choose/Just gimme that rock and roll."

And that's what "Rigor Mortis" gives you. Unabashed, sledge hammer, glandular rock and roll. Nothing more. No pretensions, no elaborate mixings, no blends of various styles, no complicated arrangements. Just rock and roll.

It's rock of the sort the Who began doing in 1963 in England when the group was into all that Eddie Cochran rock and roll. Sort of the legacy of "My Generation" and "Summertime Blues." Simple, happy, joyous rock. And, praise be, all very good rock.

The only weak link is Entwistle's voice. It's not strong enough for a lot of the material he does – like "Hound Dog" and "Mr. Bass Man."

His voice does much better on the numbers which he wrote specifically for the album – seven out of the 10. Which would seem to indicate that he probably understands his weakness fairly well.

The album's strong points outnumber the weak ones by a huge margin. First of all, there's the material. As noted, it's simple, joyous stuff. Light and breezy, good listening music.

Then there's the execution. Flawless. Nothing need be said about Entwistle's bass. All the world knows of its quality. Same goes for Tony Ashton's keyboard, Alan Ross' guitar and Graham Deakin's drums.

In addition to all that, something has to be said about the album's sly humor. It keeps cropping up in strange places and it's priceless.

Like the song "Do The Dangle," an item about various dances – the wheezy, where you pop pills and run in place; the strike, where you "stand still and do nothing/you just wait for someone else to make the first move;" and, of course, the Dangle, a dance to do on air while hanging yourself.

Then there's "Roller Skate Kate," sung to the tune of "Donna," and "Peg Leg Peggy," a song which is about exactly what you think it is.

Things like that. They keep popping up all over the album. There are about 1000 more examples.

We recommend it heartily. It's perfect summertime music.