Roger Clemens was a high school senior in Katy, Texas, when Nolan Ryan came to the Astros in 1980. On days that Ryan was scheduled to pitch, if Roger wasn't in school or off playing one of his own games, he would head to the Astrodome, sneak down to the seats by the home bullpen and listen to the Ryan Express. "It was always quiet at that time of day," Clemens recalls. "And it was indoors, so sounds were magnified. Nolan threw the ball harder than I imagined a ball could be thrown. It made a sound like a gun going off when it hit in the catcher's mitt. I'll never forget it." O Nearly two decades later, Clemens answers to "Rocket." He owns two 20-strikeout games and five Cy Young Awards and is 10th on the all-time strikeout list—with a chance to get to third behind Ryan and Steve Carlton in three years. At 36, he prides himself on being Ryan's successor—a powerful, finely conditioned machine who throws in the high 90s, 250 innings a year. "There's an aura about him that's unlike anyone in the game," says his former Blue Jay catcher Darrin Fletcher. "He stalks the mound. He talks that Texas jive. He intimidates hitters. It's all about being the Great Texas Fastball Pitcher." O In the late '60s, when Ryan made his debut in The Dome, then-Astros ace (and current manager) Larry Dierker remembers that about five pitches into the bottom of the first inning, the entire team was up along the railing in the dugout. "Normally, half the team would be back in the clubhouse," says Dierker. "But after Nolan's first pitch, guys started talking, and everyone in the clubhouse rushed down. Everyone had to see him." That's what heat does. Roger Clemens has a larger than life presence. Greg Maddux doesn't, exactly. Are they both Hall of Famers? Of course. Are they both fastball pitchers? Yes. But while Maddux is subtle, throwing from 87 to 91 mph, with sneaky late movement and precise control, Clemens is the Blue Angels roaring over the stadium. The earliest flamethrowers inspired nicknames like "Smokey" Joe Wood and Walter "The Big Train" Johnson. In the '40s, Indians righthander Bob Feller—"Rapid Robert"—was brought to a Nevada desert to match his fastball against a speeding motorcycle. (Feller's heater won.) In the late '70s, around the time highway police first began catching speeding motorists with radar, the first JUGS guns began showing up in ballparks—in the hands of scouts seated behind the screen. The readings were usually kept top secret, but word would get out that Ryan or his Astros teammate J.R. Richard was throwing 100 mph. Now, in a lot of ballparks, they post the radar gun reading of each pitch. Fans have collectively gasped, then cheered, as Mark Wohlers, Robb Nen, Kerry Wood and Matt Anderson have hit triple digits. One night in Texas, Armando Benitez angered then-Orioles manager Davey Johnson by looking back to the scoreboard to see what his pitch had registered on the Pitch-O-Meter. The Tampa Bay Devil Rays had to answer to fans in leftfield who complained they couldn't read the gun from their seats. The Rays have now added a second board. If Dierker's fastball god was Ryan, Davey Johnson's was an old minor league teammate from the Orioles organization, a guy named Steve Dalkowski. "He was short, maybe 5'8", with Coke-bottle glasses," recalls Johnson, now manager of the Dodgers. "His fastball took off like a plane, starting at the thighs and soaring right out of the strike zone. Guys were terrified." Dalkowski blew out his arm in 1965 and never pitched in the majors, but he is such a legend that everyone who played against him seems to have a story. Brian Murphy, a longtime minor league infielder who is now assistant to Braves GM John Schuerholz, faced Dalkowski in the Class A California League: "I remember thinking I'd really accomplished something because I kept fouling off two-strike fastballs. I was happy just to battle him." After the game, the Reno and Stockton teams ended up at the same party, and Murphy remembers Dalkowski wandering around with a fifth of Crown Royal. "His teammates took up a collection and bet him that when he finished the bottle, he couldn't throw it over the roof of the building across the street," says Murphy. "There was a tennis court, a pool, a small street, then the building. He stepped outside, fired the bottle over the roof, came in, collected the money and bought another bottle. What an arm he had." The ability to throw hard, really hard, remains the most sought-after tool in baseball. That's why the only thing in the game that travels faster than a 100 mph heater is a scout's car when he gets word of some kid somewhere who can bring it. A Red Sox scout named Buzz Bowers was winding his way down to Florida in 1994 when he stopped to watch a game in South Carolina between two small colleges. There, pitching for Coker College, was a 6'4", 230-pound converted outfielder named John Crowther, who threw 96 mph and looked like Clemens. Bowers tried to hide his discovery, but couldn't. Within two weeks, there were 50 scouts at every game to see "The Smoker from Coker." Toronto took Crowther at the end of the first round, but he hurt his arm and retired. "The best fastball I ever saw was Bobby Witt's when he was at Oklahoma," says Tampa Bay GM Chuck LaMar. In fact, Jim Walton of the Scouting Bureau graded Witt's arm an 80 on a scale of 20 to 80, the only perfect 80 the Bureau has ever recorded. But the Rangers rushed Witt, and when he struggled, they began to tinker with his delivery. Witt has won 131 games in a 13-year career, but he never lived up to his potential. Still intrigued, LaMar has Witt in camp this spring. "I see him throw now and I think back to that first time," LaMar says. "That's what the great fastball does. It's what you're always looking for. And when you see it, you never forget it." For every Ryan or Clemens, there are two Dalkowskis, three Witts and a hundred Smokers from Coker. We were reminded again this spring—when Kerry Wood went down for the season with a sprained ulnar collateral ligament in his right elbow—that a great arm is as fragile as it is rare. Wood, of course, hails from Irving, Texas, grew up idolizing Clemens and dreamed of being The Next Great Texas Fastball Pitcher. "We need those guys," says Braves manager Bobby Cox. "He's special, the kind of pitcher who can really pack 'em in." The kind you never forget. The kind you're about to see.

This article appears in the April 5, 1999 issue of ESPN The Magazine.