When Mark Vonnegut was growing up in Barnstable, Mass., his famous father wasn't famous yet. Kurt Vonnegut was anything but, in fact.

When Mark Vonnegut was growing up in Barnstable, Mass., his famous father wasn't famous yet.

"He was sort of a failed used car salesman, and he couldn't get a job teaching English at Cape Cod Community College. I think it would have been much more intimidating to grow up wealthy with a famous father, but I (the eldest) was out of the house (age 22) when 'Slaughterhouse-Five' was published (in 1969). But I was always rooting for him," said Mark Vonnegut, now a pediatrician in Quincy, Mass.

Kurt Vonnegut went on to establish a firm reputation as an icon and literary hero of the counterculture movement of the '60s and '70s. He was beloved by many for his satirical mix of humor, science fiction and philosophy, and his affection for society's outcasts. He left a sizeable body of work when he died in 2007 at 84. In addition to "Slaughterhouse-Five," his semi-autobiographical novel about a World War II prisoner of war who survives the bombing of Dresden, he is lauded most for "Cat's Cradle," "Breakfast of Champions" and "God Bless You Mr. Rosewater." Mark Vonnegut says his favorite work by his father usually is the last one he read, in this case, "God Bless You Mr. Rosewater."

"I love a lot of the short stories, but he and I liked a lot of his pre-fame stuff better," Mark Vonnegut said. "He often gave himself grades, and he would give 'Slaughterhouse-Five,' 'Cat's Cradle' and 'God Bless You Mr. Rosewater' A's and A-pluses, and he would give 'Deadeye Dick' a D. He could be critical of his own work."

In many ways, Mark Vonnegut thinks success was not such a great thing for his father.

"I think it was toxic. He would complain that editors didn't want to correct him," Mark Vonnegut said. "They thought everything he wrote was fantastic and that he could do no wrong. He missed the community and craft of writing.

I think (that's why) he gravitated toward theater. It was much more of a community, and directors would tell him what worked and what didn't."

It wasn't very long after his father's success – and the break-up of his parents' marriage – that Mark Vonnegut suffered a psychotic breakdown that resulted in several extended periods of hospitalization that he attributes to genetics, stress and other personal issues. Fortunately, he was able to make it through the difficulty. He documented his journey in his 1975 book, "The Eden Express," and further explored it in his 2010 book "Just Like Someone Without Mental Illness Only More So."

Mark Vonnegut said he remembers feeling the pressure of being Kurt Vonnegut's son and the possibility of following in his footsteps.

"I remember there was a party for Saul Bellow and there were all these fancy people," Mark Vonnegut said. "And, in front of everyone he (his father) said, 'Sons always take some minor talent of their father and try to beat (him) at it. What are you going to do my son?' And, I said, 'I think I'll write, Dad.'"

And he did, publishing articles in Harper's and the Village Voice. But medicine became his profession.

"I just tried to think of what I would have done if it had not been for the '60s and all the political stuff, and the assassinations of Jack Kennedy, Robert Kennedy and Martin Luther King Jr. (I thought) if it hadn't been for all that stuff, what would I have done," Mark Vonnegut said.

He gathered some steam by taking some classes at UMass Boston (he already had an undistinguished degree from Swarthmore) and was accepted to, and graduated from, Harvard Medical School in 1979 at the age of 32.

Some say that Kurt Vonnegut was a pessimist and very critical of mankind, but Mark Vonnegut has a different view.

"I think he was a real optimist. You don't write 24 books if you're a pessimist. It's hard work to write a book," Mark Vonnegut said. "I do think that George Bush and the invasion of Iraq did finally break his heart. He really thought America could be and should be the kind of paradise that Thomas Jefferson and others (envisioned). He was heartbroken by the way we were going around and beating up on smaller countries. I wish he had lived to see Obama inaugurated. Political stuff never works out the way you hope it will, but I think he would (have been happy). He often had good hope. He loved Jack Kennedy. He loved Bobby Kennedy. He loved Martin Luther King. He was a true optimist and progressive in many ways."

So did father and son end their relationship on good terms?

"Yes we did," Mark Vonnegut said. "You know, I often thought it could go either way. We really tested each other, but I am grateful that it ended well."