The Calder Memorial Trophy is an annual award presented to the most outstanding rookie player in the National Hockey League (NHL). Established in 1936, it honors Frank Calder, the first president of the NHL. The trophy is awarded based on a vote by the Professional Hockey Writers' Association at the end of each regular season. To be eligible for the Calder Trophy, a player must have played fewer than 25 games in any previous NHL season and must be a rookie in the current season. The award recognizes the talent and potential of new players entering the league.