The NBA Finals is the championship series for NBA Basketball. It was started in 1947, and was the title series for the BBA (Basketball Association of America), until the NBA was started in 1950.
The series features the winners of the NBA's Eastern and Western Conferences, in a best-of-seven series (the team with the higher winning percentage holds home court advantage). Since the Finals usually features teams from opposite coasts, to avoid extensive travel it uses a 2-3-2 format in regards to playing at home and away: the higher seeded team hosts Games 1 and 2, then the lower seeded team hosts Games 3 and 4 (and, if necessary, Game 5), and then (if needed) the higher seeded team hosts Games 6 and 7.
The Los Angeles Lakers have played in the championship the most times, with 29 appearances. The Boston Celtics have won the most titles, with 16.