Veterans Stadium was pitch black here Saturday night. Almost all of the 40,000 fans had gone home, except a few hundred who crowded in the box seats behind the visitors' dugout to bid farewell to Lou Brock.

In the dark ballpark, Brock sat bathed in the halo of a spotlight, waiting to be interviewed on TV for St. Louis.

In his red Cardinal windbreaker, with the dirt of sliding still giving his uniform the touch of reality, Brock looked like one of those bright-colored oils he paints in his spare hours - when he is not stealing 900 bases or getting 3,000 hits.

a Philadelphia fan, oblivious to the fact that just minutes before Brock had completed a single-double-triple evening by knocking in the ninth-inning game-winning run.

Brock's quiet, dignified, somewhat enigmatic face suddenly broke into t,e big all-embracing smile that he usually reserves for the privacy of the clubhouse. "T t pleased me," he said later. "Perhaps they understand...a little."

The baseball world knous th at Brock needs only 15 hits to become the 14th player to reach 3,000. And it knows that Brock is hitting .325 - or 103 points higher than that imposter who wore the Redbirds' No. 20 last year and tained Brock's good name.

Only within the Cardinal fold is it truly known what 1979 has meant to a man whose baseball life has been a testament to dignity, achievement and unfailing gentlemanliness that may be the athletic equivalent of sainthood.

"When the great man retires, $&(WORD ILLEGIBLE I'll miss him more than anyone in the game, absolutely more than anyone," says Cardinal Keith Hernandez, a .320-hitting first baseman.

"For the last two seasons, I've watched our front office try to push Lou out the door.

"But, you know, it's just like the Lord wouldn't let...." Hernandez pauses, knowing Brock loathes immodesty. "Well, it just wouldn't have been fair for him to leave the game bitter. Baseball owes him. Not the other way around. "Now, it's great to see him make everybody eat crow, to see him inside and go out with style."

The indignities of last season, with the words "washed up" and "embarrassing himself" constantly in the air, were triply harsh to a man who rose from the rural poverty of Mer Rouge, La., where he ran five miles to school to avoid bullies, to a college degree in mathematics, and finally to his current standing as a portrait pinter of professional quality.

Occasionally, the flash fires flare behind Brock's outward mask of class, as when he is asked repeatedly how he can possibly be hitting so well. "Oh, just some things I've been doing for 16 or 17 years," he says.

More often, he lowers his pilot light to simmer.

"I've seen many great ones leave the game bitter after being pushed out of th e town where they made their marks - Hank Aaron, Willie Mays, Warren Spahn. All across the board, I've seen it.

"It should be permissible," he says in his characteristic academic arms-length manner that can be as fastidious as his clothes, "for there to be exceptions to the rule of aging.

"I was subjected to a lot of things last year...mostly from within our own a sense, my integrity was at issue. I told the club my problems were technical and correctable. They chose not to believe me.

"It's nice to know that you can carve out something that's important to you - that you can get back on a collision course with that thing called desire. There's no question that 3,000 hits is a star in the crown, especially because it comes at the end."

With his measured reserve, Brock says, "I could play another year or two, if I wanted." Those are words from heaven to him. Others have let their bodies go at 40. Brock has known, though others doubted, that although he is slower, he is still as taut, strong and flabless as at 30.

"Retirement is just a matter of where you choose to hang your hat. I choose to hang it here," says Brock, who announced that he would retire after this season, long before the year began.

For Brock, who has hit an even .300 in his 16 Cardinal years, this season has been a splendid peg for that crimson cap. Once more, he is a confident, aggressive part of the game. In fact, he may top his previous batting high of .315.

"Look at this hair" says Brock, grabbing a handful of Phillie outfielder Bake McBride's huge Afro and calling it to Pete Rose's attention by the batting cage. "If I can hit one in there tonight, i'll get an inside-the-park homer before anyone can find it."

That is the other side of Brock - the dugout teaser and needler with fire in the stomach and mischief in his head.

Everyone sees the Brock that teammate and left-field caddie Bernie Carbo (wearing a "Lou-Lou-Lou - 3,000" T-shirt) calls, "The finest gentleman in baseball. He treats everyone the same - with respect."

That is the Brock that Brock reveals to the light - the analyst, the diamond scientist who has reduced base-stealing to a matter of technique and stopwatches, pop-up slides and 3.5 seconds between bases. The other Brock is for insiders only.

Ironically, Brock's batting redemption was neither a product of his constant self-analysis nor self-motivation. It was mostly luck.

With his batting average below .200 entering last September, with a pathetic five RBI in five months, Brock was groping for the ball at the plate like an old man with a cane.

One day in the cage, Brock overheard a former mate, whom he won't name, mutter, "Look at poor old Lou, hitting off his back foot...just trying to pitty-pat the ball."

That turned the lights back on. Brock hit .358 in September.

"I have always lived between two swings - a basic short spray-hitting stroke and a basic free swing," he says. "My problem is that I once hit a 500-foot homer in the Polo Grounds. I never completely decided what type of hitter I was - so I was two hitters.

"Never once in my career, except a few months in "67, did I ever have both swings synchoronized. You can't exist comfortably in both worlds.

"But," he emphasizes, "I was aggressive, probably over-aggressive if anything, with both swings. I always hit off my front foot and I attacked."

So Brock, perhaps the only 3,000-hit man who is almost never asked his theories of hitting, has become himself again at the plate - a front-foot slasher, constantly fluctuating between a power and a slap stroke, while he weaves in "several stances and several hand positions."

While Brock prides himself on being "almost impossible to scout because even I don't know from day to day what type of hitter I'll be," he has managed to reduce the universe of pitchers to simplicity itself, thanks to scientific method.

"There are only so many ways to throw the ball. Every pitcher falls into one of a few groups. tonce I decide who a new pitcher looks like, all I have to do is find out how well he changes speeds, because the changeup has always been the pitch they throw me."

Few men at 40 have turned back the clock, found their former selves - in Brock's case, actually built the highest average of his 18-year career, thus far at least.

As the countdown to 3,000 continues and Brock's name climbs toward the head of the top 10, he relishes every stop on his triumphal procession, savors that sense which he loves most of all - the knowledge that he will be missed, rather than pitied.

"For two years, we've been trying to find a replacement for Lou Brock. You know, someone who can run and hit and field," says Brock mischievously. "We've finally found the perfect replacement....

"Me." CAPTION: Picture, Lou Brock, playing his final season for the St. Louis Cardinals, needs 15 hits to reach 3,000. Only 13 players have done it. UPI