The world knows who Queen Elizabeth is, but few know her intimately. Royal biographer Robert Hardman seeks to answer that question in his new book, "Queen of Our Times": out April 5.

"Those who know the Queen well speak of her sense of humor and how cheerful and positive she is," Hardman says, according to PEOPLE magazine.

This differs from her portrayal as difficult on Netflix's hit show "The Crown," which Hardman said people who know the Queen do not see her portrayed accurately on screen.

"Many of her friends and close staff felt that she was always shown as miserable in The Crown," said Hardman, who spoke to dozens of friends, palace courtiers, and insiders while researching for the book.

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Simply put, Hardman says, the queen likes being queen.

"It's not just about longevity or hanging on. 'Yes, she is by far the longest-lived monarch in our country's history. She is at the center of the stage with her work ethic and enthusiasm. She truly enjoys her work." [Despite recent family heartaches, including the death of her husband of 73 years, Prince Philip, last April, and the continuing scandal of their son, Prince Andrew, Her Majesty the Queen "embodies the cliché 'Keep calm and carry on,'" Hardman says. "Even on the darkest days, she is an optimist and a soldier."

The Queen's "optimism and soldiering" are "a constant companion to her family.

The queen is also deeply immersed in her work, Hardman says, contradicting the misconception that "the queen is almost symbolic, just signing and smiling where she's told to go."

"Going behind the scenes at many events, she keeps the politicians on their toes."

She is a realist, Hardman says, preferring to stay in the present moment rather than dwell on the past.

"She is driven by the electricity of the present and is determined to live in the present," the senior advisor told Hardman.

And above all, Hardman said, Her Majesty is a stable constant in an ever-changing world.

"I don't think the people will realize that Her Majesty is part of the national landscape until she passes away. 'She is a very reassuring presence. As long as the flag flies over Buckingham Palace, the country will still be there tomorrow."