Over the last 15 years, the basketball world has been consumed with a mostly fruitless search for the next Michael Jordan. But while Jordan is seen as the best basketball player of all-time, finding the next Shaquille O'Neal will be just as difficult, if not more so.

He retired on Wednesday after an injury-plagued season in Boston, which began with a lot of promise but ended with him unable to stay on the court in their second-round loss to the Miami Heat.

His career spanned generations: Isiah Thomas was in his first All-Star Game and Chris Paul was in his last. And his statistics reflect that -- 28,596 points (5th all-time), 13,099 rebounds (13th) and 2,732 blocks (4th).  

Shaq had no learning curve: as a 20-year old rookie, he averaged 23 points on 56% shooting, 14 rebounds and 3.5 blocks. Dwight Howard, the closest thing to him in today’s NBA, just had the best season of his career after averaging 23 points on 59% shooting, 14 rebounds and 2.5 blocks.

By his second year, he was an All-Star. By his third, he was leading his team to the NBA Finals. His dominance became so routine that it was taken for granted.

Now that he’s a 39-year old behemoth, it’s easy to forget what a great athlete he was. Before the 1992 NBA Draft, he was measured at 7’1 303 with a 7’7 wingspan and a 35’ vertical. He was the biggest, fastest and strongest big man in the NBA as soon as he entered the league.

There hadn’t been a man of his size with the ability to soar above the rim and fly around the court since Wilt Chamberlain. He dunked the ball with such power that he tore the entire basket down several times.

Yet the focus on his athleticism often detracts from how skilled he was too. He had a great feel for the low post, combining excellent footwork with a variety of back-to-the-basket moves and an extremely underrated ability to pass out of the double team. Pau Gasol, the best passing big man in the modern NBA, has a career average of 3.2 assists; in his first 10 seasons, Shaq averaged 2.8.

So what happens when an all-time great athlete has an all-time great skill-set?

From the ages of 27-34, Shaq’s teams made five NBA Finals and six Conference Finals. The only time they didn’t -- in 2003 -- they lost to the eventual champion San Antonio Spurs. Whatever team he was on was an instant contender, when the Lakers traded him to the Heat in 2004, LA dropped 22 games in the standings while Miami gained 19.

From the ages of 27-29, he played in three straight NBA Finals, dominating the highest level of basketball in a way few others ever have.

Against the Pacers in 2000, he averaged 38 points and 16 rebounds on 61% shooting. Against the Sixers in 2001, he went up against Dikembe Mutombo, the Defensive Player of the Year, and averaged 33 points and 16 rebounds on 57% shooting. Against the Nets in 2002, he averaged 36 points and 12 rebounds on 59% shooting.  

The 2000 Lakers, built around a 28-year old Shaq, had the most dominant playoff run since the ABA/NBA merger. Their only loss came in OT and they had the highest margin of victory (+12.8) of any championship team in the last 34 years. They went 12-1 against the three other teams with the best records that year: 55-win Sacramento, 58-win San Antonio and 56-win Philadelphia.

Of the top ten players on the career scoring list, no one -- not Wilt, not Kareem, not MJ -- had a higher career field goal percentage than Shaq’s 58.2%. Most observers, even some of his own coaches, thought he never reached his full potential, and he still had one of the greatest careers of all-time.

For most of the last decade, Shaq and Tim Duncan were the Roger Federer and Rafael Nadal of basketball. In the eight seasons after Jordan’s retirement, the championships went: Duncan, Shaq, Shaq, Shaq, Duncan, Pistons (who beat Shaq in the Finals), Duncan, Shaq, Duncan.

Somehow, the two won only 3 MVP’s in those eight years. People saw Jordan’s success in the 90’s, when he won 6 championships without an All-NBA caliber big man, and figured that the flashiest perimeter player who “wanted it” the most was the key to a championship.

Much of Jordan’s case for all-time greatness rests on those six championships, but he never faced a seven-footer the caliber of a prime Duncan or Shaq in any of those playoff runs. The Bulls championship seasons coincided with a down-period for centers: Jordan played the Lakers two years after Kareem retired, never saw Hakeem in the Finals, went 1-1 in the playoffs against a young Shaq and missed Duncan’s career entirely.

And as Duncan and Shaq have aged, no center has emerged to take their place. Dwight Howard isn’t nearly as skilled, while injuries have destroyed Yao Ming and Greg Oden’s careers. That, more than the elimination of the hand-check, is why the NBA has become so perimeter-oriented in recent years.

Shaq himself said he wants his kids to model their games after Dirk Nowitzki -- a seven-footer who uses finesse instead of power, who prefers to face up rather than play with his back-to-the-basket, and is as dangerous from 25-feet as he is from 5-feet away.

Very few things described as “once in a generation” actually are, but Shaq entered the league exactly 20 years after Wilt retired. It might be even longer before we see another player like him.