(CNN) Arizona Republican Sen. John McCain wanted to give the big speech he delivered last summer about Senate dysfunction before he was diagnosed with brain cancer .

The senator hadn't been feeling well, and his longtime aide, speechwriter and close friend Mark Salter was waiting to hear from McCain about test results.

But when McCain called from Arizona, he launched into a conversation about what he wanted to say in his speech, asking Salter when he was coming out to work on it. Salter had to stop him and ask if he had gotten the results back.

"It's not good, not good," Salter remembers McCain saying obliquely.

Salter soon learned the grim reality of McCain's cancer diagnosis, rushed to Arizona, and the two men finished writing the address on the plane back to Washington -- just days after the senator's brain surgery. It was a trip his doctors advised against.

But the dramatic Senate floor speech he returned to deliver, after voting against his party's effort to repeal the Affordable Care Act -- more commonly referred to as Obamacare -- became one of the most emotional, memorable events in modern Senate history.

"As I stand here today -- looking a little worse for wear, I'm sure -- I have a refreshed appreciation for the protocols and customs of this body, and for the other 99 privileged souls who have been elected to this Senate," McCain said, before begging his colleagues to start working across party lines and showing respect for one another again.

"They all stayed in their chairs for his speech," Salter recalled. "That had never happened in his career, and it meant a great deal to him."

The final chapter

McCain and Salter were already working on their seventh book together, which instantly took a reflective turn.

"He wanted it to be more personal, and to convey just how fortunate he believed he was for being able to serve this country for 60 years," Salter told CNN about the book.

"What America means to him and what he thinks America means to the world, and what he hopes it will continue to mean to the world after he's gone."

The result is "The Restless Wave," being released this week.

McCain is not well enough for a book tour, so it is falling to Salter -- the man behind the scenes with the Arizona senator for 30 years -- to promote it.

"Restless Wave" is a line from the Navy Hymn, which perfectly describes the son and grandson of admirals, a former naval aviator who never stops moving.

"Only God can restrain John McCain's restlessness, that's for sure," jokes Salter.

Lieberman for VP

This new book allows McCain to tie up some loose ends. He publicly admits for the first time that during his 2008 presidential run, his dear friend then-Sen. Joe Lieberman was his first choice for his running mate.

"His aides, among them myself, had persuaded him that it wouldn't be possible," Salter explained.

They told McCain putting a Democrat turned independent on a Republican presidential ticket would spark a convention revolt.

But while McCain expresses his preference for Lieberman, he is careful not to express any regret for picking then-Alaska Gov. Sarah Palin, which multiple close associates say he has never done -- even in private.

The Dossier

McCain also explains in detail being approached in 2016 with the now famous dossier about President Donald Trump.

"He got it, he read it, he put it in his safe, he told no one. He went over to see the FBI director at his earliest convenience and delivered it to him and said, 'I assume you will vet this' and was assured they would, and that they had already known about it," Salter said.

"I discharged that obligation and I would do it again," writes McCain, in a very McCain-esque sentence. "Anyone who doesn't like it, can go to hell."

Trump

McCain spent nearly four decades in Congress sparring with Presidents in both parties.

When he first arrived in the House in the early 1980s, he criticized Ronald Reagan for sending US troops to Lebanon (he was later proved right after a Marine barracks was bombed). He slammed Bill Clinton for not doing enough during the Bosnian civil war.

But he makes clear that his concerns about Trump are much more fundamental.

"The world is learning to live without our active leadership," wrote McCain. "That's not good for the world and it won't be good for us."

A chief worry about Trump is a lack of interest in standing up for human rights around the world.

"They're very different people" Salter said dryly. "John himself comes from a long military tradition of service for this country. President Trump is rather new at that."

Defender of human rights

It is clear McCain wants this book -- sure to be his last -- to be a guide for standing up for oppressed people around the globe, as he has done for decades.

One of many stories he tells is of visiting Myanmar, formerly known as Burma, in 2012 and meeting three men who had just been released after some 20 years in prison.

"They were emotional when we were introduced. One wept when I started to speak. My disembodied voice had become familiar to him from Voice of America and Radio Free Asia broadcasts. They embraced me over and over again and thanked me profusely as if I had saved their lives when all I had done was mention their names every now and then," McCain wrote.

McCain added, "We don't always appreciate as we should the value others place on the public statements of American officials."

To be sure, McCain is no ordinary public official. He is not only outspoken on the world stage, he also has moral authority after having been brutally tortured for much of the five and a half years he was held as a prisoner of war in North Vietnam.

An entire chapter of his new book is dedicated to arguments against torture, profusely criticizing America's post 9/11 torture tactics, as he did in real time during the George W Bush administration.

For over 30 years, Salter has helped McCain convey his essence -- writing thousands of words for and with McCain.

When asked what he thinks are the most important of all, Salter paused, and quoted from one of their books, "Why Courage Matters."

"We were born to love, and we were born to have the courage for it. So be brave, the rest is easy," recites Salter, getting understandably choked up as he does.

"I thought that was the most McCainesque thing he ever said," he added.

Love of literature

Had he not been born John Sidney McCain III, the son and grandson of four-star admirals, McCain has often said, he could have easily studied literature and become a professor rather than join the Naval Academy.

His favorite author is Ernest Hemingway, and his favorite book is "For Whom the Bell Tolls." The main reason is because of the protagonist Robert Jordan's romantic love of country, and fighting for a lost cause just because it was honorable

"After your father and grandfather, who is your biggest hero?" Salter remembers asking McCain once.

"And the first person he named was Robert Jordan, and I scratched my head. It had been since high school, since I read the book. And when I finally determined who it was I said, 'Well you know it's a fictional character.' 'He's as real to me as you are,' Is what he told me, 'And he was important to me,'" Salter said.

So it is no surprise that on the final full page of his final chapter, after talking about how lucky he has been to have known great passions, fight in war and make peace, McCain quotes Jordan, his hero.

"The world is a fine place and worth fighting for and I hate very much to leave it."