Lynn Nolan Ryan Jr. (born January 31, 1947), nicknamed "the Ryan Express", is an American former professional baseball pitcher and sports executive. Over a record 27-year playing career in Major League Baseball (MLB), Ryan pitched for the New York Mets, California Angels, Houston Astros, and Texas Rangers. After his retirement in 1993, Ryan served as chief executive officer (CEO) of the Texas Rangers and an executive advisor to the Houston Astros. He was inducted into the Baseball Hall of Fame in 1999 in his first year of eligibility, and is widely considered to be one of the greatest pitchers of all time.

Ryan was a right-handed power pitcher who consistently threw pitches that were clocked above 100 miles per hour (161 km/h), being one of the first pitchers to officially be able to do so. He maintained this velocity throughout his pitching career, being known as one of the top pitchers in Major League Baseball into his mid-40s. Ryan was also known to throw a devastating 12–6 curveball at exceptional velocity for a breaking ball.

Ryan had a lifetime win–loss record of 324–292 (.526) and was an eight-time All-Star. He has 5,714 career strikeouts, an MLB record that is 839 more than runner-up Randy Johnson. Similarly, Ryan's 2,795 bases on balls lead second-place Steve Carlton by 962 – walking over 50% more hitters than any other pitcher in MLB history. Ryan's lifetime batting average against of .204 is also a major league record. He recorded 300 strikeouts in a season six different times, a Major League record, and 200 strikeouts in a season 15 times, also a Major League record. Ryan, Pedro Martínez, Johnson, Trevor Hoffman, Sandy Koufax, and Billy Wagner are the only six pitchers inducted into the Baseball Hall of Fame who had more strikeouts than innings pitched. Ryan is one of three players in history to have his number retired by at least three teams, along with Jackie Robinson (whose number was retired by Major League Baseball) and Frank Robinson.

Ryan is the all-time leader in no-hitters with seven, three more than any other pitcher. He is tied with Bob Feller for the most one-hitters, with 12. Ryan also pitched 18 two-hitters. Despite this, he never pitched a perfect game, nor did he ever win a Cy Young Award; both were largely attributed to his high walk rate. Ryan is one of only 31 players in baseball history to have appeared in MLB games in four different decades, and retired over 7 years later than the next longest-tenured player of the 1965 Major League Baseball draft, Tom Seaver.

Lynn Nolan Ryan Jr. was born on January 31, 1947, in Refugio, Texas, a small town located just south of Victoria in the southern part of the state. Ryan was the youngest of six children born to Martha Lee (née Hancock; 1913–1990) and Lynn Nolan Ryan Sr. (1907–1970). The senior Ryan operated a newspaper delivery service for the Houston Post that required him to rise in the early morning hours to prepare 1,500 newspapers for delivery over a 55-mile (89 km) route. The children were expected to help with the daily tasks. Ryan's family lived in nearby Woodsboro, Texas, in Refugio County, until they moved to Alvin, Texas, in Brazoria County, when Nolan was six weeks old. As a young boy, Nolan enjoyed throwing objects at any target. His father thought baseball was a better usage for his arm; therefore, he encouraged Nolan to play the game.

Ryan joined Alvin Little League Baseball when he was nine, made the all-star team when he was 11 and 12, and pitched the first no-hitter of his life a few years later. Ryan also played various positions besides pitcher. In junior high school, Ryan could throw a softball over 100 yards. After ninth grade, Ryan quit playing football after a tackle and fumble caused by future NFL running back Norm Bulaich made him decide to focus on baseball.

Ryan played baseball for Coach Jim Watson at Alvin High School for all of his high school career. Ryan held the school's single game strikeout record for 44 years, striking out 21 hitters in a seven-inning game. The record was tied by Alvin High School pitchers Aaron Stewart and Josh Land in the same week in 2009. In 1963, at an Alvin High School game at Clear Creek High School in League City, Texas, Red Murff, a scout for the New York Mets, first noticed sophomore pitcher Ryan. Coach Watson recounted to Murff that some opponents refused to bat against Ryan and how his hard pitches would sometimes break bones in his catchers' hands. In his subsequent report to the Mets, Murff stated that Ryan had "the best arm I've seen in my life." As a senior in 1965, Ryan had a 19–3 record and led the Alvin Yellow Jackets to the Texas high school state finals. Ryan pitched in 27 games, with 20 starts. He had 12 complete games, with 211 strikeouts and 61 walks.

After he graduated from Alvin, the New York Mets selected Ryan in the 12th round, with the 295th overall pick, of the 1965 Major League Baseball draft. Ryan signed with the Mets and pitched for the Marion Mets in the Appalachian League and for the Mets team in the Florida Instructional League. Overall, he was 6–9 in 1965 with a 4.33 earned run average (ERA) and 150 strikeouts in 120 innings. In 1966, Ryan pitched for the Class A Greenville Mets of the Western Carolinas League, where he went 17–2 with a 2.51 ERA and 272 strikeouts in 183 innings. He was then promoted to the Class AA Williamsport Mets of the Eastern League, where he was 0–2 with a 0.95 ERA, striking out 35 batters in 19 innings. Overall, Ryan had 307 strikeouts in 202 minor league innings in 1966, earning a late-season call-up to the New York Mets. In 1967, Ryan pitched three games in relief for the Class AAA Jacksonville Suns, started one game for the Class A Winter Haven Mets and pitched eight games for the Mets team in the Florida Instructional League. In 34 total innings, Ryan had 54 strikeouts in 1967.