Blackhawks chairman Rocky Wirtz may be the son of his predecessor, Bill Wirtz, but his ascension to power wasn’t inevitable. In The Breakaway (October 1, Northwestern University Press), commissioned by Rocky, Chicago senior writer Bryan Smith delves deep into the elder Wirtz’s strange tenure at the top. Four things you’ll learn:

1 Bill wrote legendarily scathing letters.

After suffering a stroke, he sent meticulously crafted hate mail and faxes to politicians, businessmen, league officials, and even family members. “I’d hear something arriving — you know that sound a fax makes — and I’d see the cover sheet with the Blackhawks logo scrolling up and the hair would stand up on the back of my neck,” NHL commissioner Gary Bettman says in the book.

2 Bill showed signs of dementia while still running the Hawks.

One time he got lost while driving to a downtown board meeting and ended up in Aurora, 40 miles west. He also accused his sister Betty of gossiping about him. “He was always so sweet and loving toward me,” she says. “I had never seen him act that way.” When she wrote to him insisting she would never betray him, he’d forgotten the whole thing.

3 Bill tried to keep Rocky out of power.

“[He] would do this divide-and-conquer stuff, where he’d communicate his anger through other people,” Rocky says. Bill shut his son out of secret meetings with his younger son, Peter, whom he planned to install as heir to the Hawks, even though Rocky was next in line in the succession plan laid out by their grandfather. But Peter was out of luck: “Dad didn’t own the Blackhawks, the company did,” says Rocky.

4 Rocky advised his siblings against a pregame tribute 11 days after his dad died in 2007.

He recalls offering this warning after relenting: “Fine. Go for it. But I don’t think you’re going to like the reaction.” The ensuing jeers during a moment of silence, he says, cemented his ambition to change the team for the better.