In the hours following a big win, NBA players often hit the town and kick back with a celebratory dinner — and perhaps a cocktail or two.

But after a recent day’s worth of sweat and floor burns, Dwyane Wade was anything but a man on the town. He spent the evening with his eldest son, Zaire, hitting the books.

“I came over to his house and found them in the kitchen, doing homework,” said Wade’s mother, Jolinda. “Watching the interaction, with Dwyane putting it in a way where his son could understand. Once he got it, they high-fived and hugged.”

Here’s a little secret: Of all the names Wade goes by — D-Wade, Flash, MV3 — there’s one he holds most dear: Dad.

Wade — who will spend Father’s Day 2012 on sports’ center stage as his Heat hosts the Oklahoma City Thunder in the NBA Finals’ pivotal Game 3 — regularly uses his Twitter account as an open love letter to his two boys, Zaire and Zion. He also maintains a blog on parenting issues in partnership with Pepperidge Farm.

While every proud musing and family photo he posts is seen by his 3.3 million Twitter followers, here’s something his army of loyal fans might not know: Wade has penned a book on fatherhood that’s due to hit stores in September.

It’s self-evidently entitled A Father First: How My Life Became Bigger Than Basketball.

Wade may be passionately devoted to his sport, but he calls fatherhood “the single most significant undertaking of my life, and the job I take most seriously.”

During a break in Saturday’s practice at Miami’s AmericanAirlines Arena, he elaborated: “Anyone who’s a father, you know it’s one of the most special things … and one of the purest relationships that you have in life. I enjoy being one of the guys with my boys, but I also enjoy being a leader and being able to lead them and help mold the way that they think.”

This time last year, three months after winning full custody of his two sons after a bruising custody battle with ex-wife Siohvaughn Funches, Wade authored a piece for Newsweek magazine on life as a single dad. Wade wrote then how the stresses of being a key player on pro sports’ most polarizing team wash away every morning when he wakes his kids for school.

Wade’s bitter, public divorce had limited his time with his boys, and the resulting emptiness convinced him he wanted to be a full-time dad in addition to a full-time star. Around the same time Wade was winning custody of Zaire and Zion, President Barack Obama asked him to be part of a national parenting program intended to persuade fathers to become more involved in their kids’ lives.

Now, Wade’s putting the finishing touches on the book, his first. While the publisher, William Morrow, has not made advance copies or excerpts available, company publicists chose Father’s Day week as the best time to begin generating buzz for the work, due out Sept. 4.

They promised never-before-heard accounts of Wade growing up in a broken family in the town of Robbins, a hard-luck suburb of Chicago, and insight into his explosive break-up with Funches, his high-school sweetheart. The book will include personal accounts of Jolinda Wade’s past drug addiction, how moving in with his father Dwyane Sr. as a boy helped salvage his life, and the ways in which the constant media attention has affected his own boys.