Nathan Michael Lyon is an Australian international cricketer. He made his Test debut in 2011 and plays domestic cricket for New South Wales. Lyon is an off-spin bowler and a lower-order right-handed batsman. Considered the most successful off-spin bowler of all time for Australia, Lyon holds the record for the most Test wickets taken by an Australian off-spin bowler, passing Hugh Trumble's 141 wickets in 2015. In January 2021, Lyon played in his 100th Test match during Australia's series against India. As of December 2023, Lyon is Australia's third highest test wicket taker of all time and ranks eighth among all international players in test cricket with over 500 wickets to his name. Lyon was a member of the Australian team that won the 2023 ICC World Test Championship final.

Test cricket is a form of first-class cricket played at the international level between teams representing full member countries of the International Cricket Council (ICC). A match consists of four innings in which players have to play until they get all batsmen out; the match ends when all but one of the batsmen of the opposing team are out. It is scheduled to last for up to five days with 6 hours of play each day. A minimum of 90 overs are scheduled to be bowled per day making it the sport with the longest playing time. In the past, some Test matches had no time limit and were called Timeless Tests. The term "test match" was originally coined in 1861–62 but in a different context.