Star Trek fans may remember the controversy surrounding Leonard Nimoy’s funeral in 2015. That controversy centered on William Shatner, who did not attend the ceremony. Shatner has addressed this in his new book, sharing his thoughts about his former friend.

The book is a memoir titled Live Long And...What I Learned Along the Way. Trek Movie received an advanced copy of the book, in which Shatner reflects on Nimoy’s passing.

Fans will remember that Shatner skipped the funeral because he had a Red Cross fundraising event to attend, causing a scheduling conflict. His daughters attended the funeral in his place.

In the book, Shatner admits that his absence came from someplace deeper. Those reasons were rooted in his once-close friendship with Nimoy that had gone cold for reasons he says he still is unaware of.

“It was made clear to me that I was not welcome at his funeral,” Shatner writes. "That was painful. I had an easy excuse."

“My closest friend was Leonard Nimoy. We were born four days apart and raised in Orthodox Jewish homes. We shared so much throughout our careers. I loved Leonard, and he used to refer to me as his brother. Yet at the end of his life and for reasons I still don’t know, he was not my friend. I would call him and he wouldn’t answer the phone or return any messages. He died and I didn’t feel welcome at his funeral,” he adds.

In Shatner’s 2016 book Leonard, which focused on his relationship with his Nimoy, Shatner said he hadn't spoken to Nimoy for five years before his death. This was after Shatner filmed Nimoy without permission for the Star Trek documentary The Captains.

“I thought he was kidding,” Shatner said of Nimoy’s refusal to appear in the film. “It was such a small thing.”

But five years passed and Nimoy never reconciled with Shatner. Based on Shatner’s new memoir, it seems he may still believe that the footage used in the documentary was too small of a thing to create that rift. Now he is left wondering what the real root of the problem was.

What do you think of what Shatner wrote in his memoir about Nimoy’s funeral? Will you be picking up the book? Let us know in the comments section.

Live Long And...What I Learned Along the Way by William Shatner goes on sale today.