There are teachers and then there are teachers – Aristotle, who taught Alexander the Great; Annie Sullivan, who unlocked the brilliance of Helen Keller; Jelena Gencic, who taught Novak Djokovic poetry and classical music along with groundstrokes.

Nick Bollettieri is a teacher. Watch him talking to kids who’ve been practicing tennis on one of the 10 indoor courts in the gorgeous new Lifetime Athletic in White Plains, N.Y. He doesn’t just autograph his new book, “Changing the Game” (New Chapter Publisher, 319 pages, $26.95), for them. He takes the time to explain the fine points of the game – their game. And the kids, hardly bigger than the tennis bags they are carrying, really listen.

Even his inscription in my copy is a teacher’s admonition: “You have studied the game. But remember it’s people that you must know in order to give more precise information.”

To Nick, that’s what makes a great coach – the ability to know the individual student to help him become the most he can be.

Nick grew up in Pelham, N.Y., playing football and thinking tennis was a sissy’s game. But then an uncle who belonged to the New Rochelle Tennis Club invited him to join him there and, well, football’s loss was tennis’ gain.

Nick has coached 10 world No. 1s, including the Williams sisters, Maria Sharapova, Andre Agassi and Monica Seles. It was Seles who surprised him at Madison Square Garden on World Tennis Day March 3 to introduce him as one of this summer’s inductees into the International Tennis Hall of Fame.

I’m smart enough not to ask who his favorite is and instead ask who is the best he ever coached. He answers the question by turning it around.