20 YEARS YOUNGER: Look Younger, Feel Younger, Be Younger! by Bob Greene, with Harold A. Lancer, M.D., Ronald L. Kotler, M.D., and Diane L. McKay, PhD. Little Brown and Co., 314 pp., $27.99.

Oprah's trainer/ bestselling author/

advertisement | advertise on newsday

Nintendo Wii exercise guru Greene has forayed again into diet/fitness/looking-good land (his last book came out in January), this with an eye to baby boomers.

Who wouldn't want to look, feel and actually be younger? After all, most of us aren't.

Here, Greene emphasizes what he calls The Four Pillars (just one short of a major religion's) -- Exercise, Diet, Skin Care and Sleep.

THE SCOOP Greene gives tips on cardio, strength- training exercises and more; his diet emphasizes fruit and veggies, whole grains, healthy fats and supplements. No surprises. Plus, using sunscreen, washing your face and sleeping in a darkened room.

THE BOTTOM LINE There's a chapter on "Putting It All Together" -- when to wake up, exercise and "polish, cleanse, nourish" your skin. Not to mention turning out that light -- you'll sleep better without the late-night news. Yawn.