They say 40 is the new 30, but in the world of professional sports, this saying became vividly apparent at the turn of the century.

		"GAME OF SHADOWS: BARRY BONDS, BALCO, AND THE STEROIDS SCANDAL THAT ROCKED PROFESSIONAL SPORTS" By Mark Fainaru-Wada and Lance Williams Gotham ($26) Related review 'Love Me, Hate Me: Barry Bonds and the Making of an Antihero' by Jeff Pearlman

At 39, slugger Barry Bonds produced the third best offensive season of his career, hitting .362 with 45 home runs and 101 RBIs.

This performance was molded from the steroids and related drugs administered to Bonds and many other star athletes by the Bay Area Laboratory Co-Operative, or BALCO, charges this new book by two San Francisco Chronicle reporters.

In December 2004, Lance Williams and Mark Fainaru-Wada broke the story of how this shady operation became integral to the performance of high-profile athletes, including 2000 American League MVP Jason Giambi, Olympic sprinter Marion Jones and former National Football League linebacker Bill Romanowski.

The story begins in California's Central Valley, where Victor Conte was first a musician who nearly made it as a band leader. After several failed ventures, he reinvented himself as a nutritionist to star athletes.

The food chain from snake-oil salesman to Olympian consultant is shockingly quick, and the authors, who are first-rate gumshoes, do the legwork to connect all the dots.

Along the way, they remind us that steroids in sports have been with us a long time, from the doping programs of East Germany through the disgrace of Canada's Ben Johnson at the 1988 Olympics in Seoul.

Sophisticated drug testing has been developed to keep the Olympics clean (or somewhat clean, as "Games" would imply), but Conte focused on providing illegal performance-enhancing drugs that would elude detection.

Obtaining these drugs involved some complicated schemes, reported with true-crime flair. It is surprising just how many athletes signed on for this Frankenstein regimen and how, with the help of Conte's myriad drugs, they saw dramatic turnarounds in their careers.

Bonds' results were startling, the authors show, pointing out that in his first 13 seasons, he averaged .290, 32 home runs and 93 RBIs a year. In the six years on performance-enhancing drugs starting at age 34, his batting, home runs and RBIs averaged .328, 49, and 105.

Fainaru-Wada and Williams portray the Giants star as a superbly talented athlete who developed into an indulged egomaniac troubled by the shadow cast by his father, ex-Major Leaguer Bobby Bonds, and eaten up with jealousy over Mark McGwire's success in breaking Roger Maris' home-run record in 1998.

Before that year, Bonds had refrained from cheating. But after seeing a "juiced" McGwire break the record, he was fed up.

The evidence amassed here against Bonds' denials about using banned substances is overwhelming.

Helping to break the case against BALCO was IRS agent Jeff Novitsky. An experienced investigator, he went after the BALCO case with dogged determination.

Next month, Bonds will begin his race to top Hank Aaron's record of 755 home runs, and it seems a safe bet, barring injury, that he will match it.

As to what he will say during his victory speech or how it will be received, one can only speculate. But after finishing this important and disturbing book, it's hard not to feel it will be an empty accomplishment.