William Shatner talks new book 'Boldly Go,' death and Leonard Nimoy: 'He loved me as I loved him'

William Shatner is facing the real final frontier for all humans: our inevitable death.

At 91, the most famous “Star Trek” captain, who made history as the oldest space traveler last year with Blue Origin, writes as if the Earth is floating past his capsule window in his new collection of personal essays, "Boldly Go: Reflections on a Life of Awe and Wonder" (Atria, 256 pp., out now).

“I’ve gotten to the point where I'm thinking, 'I'm breathing here. I must be alive.'" Shatner tells USA TODAY. "The concept of death is not unfamiliar to me. So what am I thinking and how am I dealing with that?"

Shatner spoke to USA TODAY about how his friendship with the late Leonard Nimoy has sprung back to life (as if on the life-renewing Genesis Planet) and his overall hopeful message.

"I'm trying to show how we're all united by every means possible," he says. "And how that unification is the unification of the universe."

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William Shatner. That's all. Just William Shatner.
William Shatner. That's all. Just William Shatner.

Q: 'Boldly Go" discusses the minor final fight and strained relationship with Leonard Nimoy toward the end of his life. What caused the rift?

William Shatner: No rift. Just a separation. I never understood it. I kept trying to get ahold of him, sending him messages. When you get really ill, you don't want to see anybody. Maybe that was it. And he died, and I thought, "What happened?" Then I thought, "Well, it's me again, I guess." But his daughter (Julie) came to me and said, "He loved you." The universe is sending me messages back that whatever happened, he loved me as I loved him. Like a brother. He was my brother. We shared a lifetime.

Nichelle Nichols, who died in July, broke the news to you that "Star Trek" cast members found you difficult during and past the TV show's famed run. You had no idea?

Total shock.

Still shocked, with all the years to reflect and writing in this book?

I have no idea what they're talking about, which may mean they're prejudiced or I'm so inured to people's reactions that I'm living in my own little world. And I don't know which it is. I strive every day to find out. It's so bizarre that I've ceased to talk or think about it. Because I think they are the problem, not me. It's a really good attitude to have in life. Isn't it?

There's time to extend an olive branch to George Takei, who called you a "guinea pig" after your Blue Origin flight. Might you?

Why would George Takei put that in public? After I came down from space – had this experience, talked about global warming – he would say, "Oh, they probably used him because he was the oldest guy that would go up." He was so mean-spirited. Again, there is no reason. And I don't give a cup of tea what his opinion is. But that's a guy who's not well.

William Shatner on Blue Origin: Still reeling from his trip to space: 'We all need a wake-up call'

You admit that you were serious in 1968's album "The Transformed Man" as opposed to playing some cosmic joke. Please explain.

When I was asked to do an album, I said, "I've got this concept of great literature with music underneath it and segue to what is great literature today, which is the songs." Which I did with great enthusiasm for living. I thought it was very avant-garde. But it just didn't work. I yearned to make music even though I can't sing. Yet, I'm poetic.

Your music has come to be vindicated in collaborations with musicians such as Ben Folds and hit albums. But what was it like to see Johnny Carson mouth an expletive as you sang "Tambourine Man" on "The Tonight Show"?

Luckily, I finished the song. I had some awful experiences with Johnny Carson. I was invited on his show a number of times, and I apparently was successful sometimes. But he would get a hate-on for people like, you're not coming back.

Did writing this book help come to terms with dying?

It helps because the fear of death is based on the unknown. I'm going to leave my home, leave everything behind and never see my loved ones again. These thoughts assail me. I'll never do another USA TODAY interview. I'm not religious. It's like, will I go through the pearly gates and God's going to bring me to everybody from my past? My dad died at 68. Can you make him 50? I'll use the neutral word. It's such an interesting way of thinking of the afterlife. That's difficult for me to come to grips with. Writing a book was fun. But it's still just as confusing as it ever was.

What do you think happens when we die?

I tend to think it's just over. You die and that's it. Your body goes back. I want to be a tree. I'm going to have my ashes taken and plant a tree over them. A redwood tree. So instead of a piece of stone, there's this living thing that is nourished by my remains and continues on.

This article originally appeared on USA TODAY: William Shatner's 'Boldly Go': Talks dying, 'Star Trek,' Leonard Nimoy