Nicholas James Bollettieri was an American tennis coach. He pioneered the concept of a tennis boarding school, and helped develop many leading tennis players during the past decades, including Andre Agassi, Jim Courier, Monica Seles, and Mary Pierce. He also worked with players such as Maria Sharapova, Daniela Hantuchová, Jelena Janković, Nicole Vaidišová, Sabine Lisicki, Sara Errani, Tommy Haas, Max Mirnyi, Xavier Malisse, Venus Williams, Serena Williams, Martina Hingis, Anna Kournikova, Marcelo Ríos, and Kei Nishikori. Bollettieri was also a tour traveling coach, the last time having been for and with Boris Becker for a span two years.