Anderson Cooper, Gloria Vanderbilt strengthen bond through memoir

Anderson Cooper, Gloria Vanderbilt on family,... 08:58

Anderson Cooper's dad died when he was just 10 years old, but for years, he clung to his fantasy that one day, he'd discover a surprise letter from his father "that would show up one day, telling me all the things I didn't know about him and all the things he wanted for my life," Cooper told "CBS This Morning" Thursday. "And of course, there was no letter."

Gloria Vanderbilt has been in the public eye ... 08:48

Cooper did not want to experience the same sense of void with his mother, heiress Gloria Vanderbilt. When the 91-year-old got sick, Cooper began to open up and get to know his mother better via email conversations that they wove into their new memoir, "The Rainbow Comes and Goes: A Mother and Son Talk About Life, Love and Loss."

"I didn't want anything left unsaid between us," Cooper said. "And I think many adult children want that... and don't really know fully about their parent."

But before that, Cooper said he wanted to distance himself from his mother because of her famous name.

"I wanted people to know me as me," Cooper explained. "That name 'Vanderbilt' has such baggage with it and such history."

Vanderbilt essentially was born in the spotlight, to the multi-billionaire Vanderbilt family. She went on to establish herself as an artist, author and jeans designer. But when she was just 10 years old, she was the center of an ugly custody battle.

Despite his initial sense of detachment, Cooper said he realized how similar he was to his mother, especially in their "drive" and "relentless determination to move through whatever befalls us."

Ten years after his father's death, Cooper's older brother committed suicide by jumping off the balcony of the family's New York City penthouse, before his mother's eyes. In a new HBO documentary, "Nothing Left Unsaid," Cooper opens up about the family's losses.

Anderson Cooper talks to his mom about sex 02:03

Still, Vanderbilt displayed her positive outlook on life, saying it was in her nature to be "hopeful" and "think something wonderful is going to happen." Even now at 92, Vanderbilt said she is "always in love" and believes her next love is just around the corner.

As documented in the memoir, Vanderbilt also opened up to Cooper about the most personal details of her life, including her romantic love affairs with high-profile stars like Frank Sinatra and Howard Hughes.

Through this shared experience with his mother, Cooper said the most important lesson he took away was that it was "never too late to change your relationship with somebody in your life."

"You just have to put aside your sort of past resentment or embarrassment or all the things we all have with our parents growing up and see the person in a new way."

We're LIVE with Anderson Cooper and mom Gloria Vanderbilt with a look at her new book #TheRainbowComesAndGoes via Vladimir Duthiers:

Posted by CBS This Morning on Thursday, April 7, 2016