Inside the Queen Mother's Close Bond with Future King Charles — and Her Cheeky Moments with Prince William!

Queen Elizabeth II and the future King Charles III were incomparably influenced by Queen Elizabeth The Queen Mother.

The mother of the late Queen and grandmother of the current King died at the age of 101 in 2002. Her captivating life story inspired the hundred-plus collection of vignettes historian Gareth Russell shakes, stirs and serves in the new book, Do Let's Have Another Drink!: The Dry Wit and Fizzy Life of Queen Elizabeth the Queen Mother , which is excerpted below. Ahead of its release, Russell exclusively spoke to PEOPLE about why the Queen Mother was so beloved by the public, how she shaped Charles as King and what she'd tell him today.

The author notes that Queen Consort lived through World War I as a young woman, rose to the throne following the unexpected abdication of her brother-in-law Edward VIII and supported her husband King George VI through World War II. She was also a widow for almost 50 years, and guided her daughter as Queen through a changing 20th century— "the embodiment of keep calm and carry on."

Summing up her spirit, he quoted a well-wisher who saw Queen Mother during a royal stop in Belfast, Northern Ireland, in 1942 — where "a touch of the imp" shined through her steely exterior.

"What they meant by that was, you got a sense that there was fun," Russell says of Elizabeth's punchy personality. "The people liked that she liked to drink. They also admired that she'd stayed in London during World War II. A fusion of a sense of fun and a sense of duty, that was the secret to the cocktail of her popularity."

Later in the book, Russell breaks down why the Queen Mother was like a second mom to Charles, 73.

"In some ways, the Queen Mother was a mother figure to Charles just because the Queen became Queen when Charles was so young. There were a lot of tours of the Commonwealth and every time the Queen had to go away, Prince Charles stayed with the Queen Mother," Russell tells PEOPLE. "They had a great sense of humor, and she always encouraged him."

Today, Russell trusts that the royal matriarch would be proud of Charles as he steps up as sovereign.

"Apparently she always said, 'Well done' to people. I think she would say, 'Well done' to King Charles, because she absolutely adored him, and she believed in things being done in a certain traditional way. I think she would've been very approving of the way Elizabeth II was buried."

As a new royal era begins, Russell says the Queen Mother would have argued against Charles' vision for a slimmer modern monarchy.

"She wasn't a believer that things had to change. I don't think she would necessarily support many of the changes that King Charles will be implementing, but she certainly would support him," Russell adds.

Read on for two exclusive excerpts of Do Let's Have Another Drink! (out Nov. 1).

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"Is it just me or are the pensioners getting younger these days?" the Queen Mother asked as she sailed into her tenth decade.

"Only the kind of person who kicks kittens, snarls at babies and denies the existence of Santa Claus," concluded one of her admirers, "can resist her jolly face, her utter femininity, her guileless way of steam-rollering through any situation."

She needed those steam-rollering skills in the Nineties. The period was difficult for the monarchy. The Queen, who had consulted her mother throughout her reign, relied on her particularly in the first half of the decade. Tabloid intrusion into the lives of the younger royals reached such intensity that it contributed to the Princess of Wales's untimely death, two years after her divorce and five years after her separation from Prince Charles. Prince Andrew and his wife Sarah divorced in 1996. Their phone lines hacked, private conversations recorded and photographers hiding in the bushes to snap them poolside became occupational hazards for the younger generation. Press intrusion was not helped by some of the younger royals' own actions, as they flitted between complaining about the media and arranging sit-down inter-views or tipping off photographers about where to find them. A sotto voce "Oh gosh, not this again" from the Queen Mother as she saw yet another headline about her grandchildren or their spouses became a frequent morning occurrence at Clarence House.

The Queen Mother did not like any of these family matters to be brought up in conversation, and she had different tactics for killing the topic. For staff, it was froideur, as an equerry learned when he asked her if she had seen Prince Charles's "tell-all" interview with Jonathan Dimbleby, broadcast the night before.

"The look she gave me could have frozen fire," he recalls. A second later, she smiled coldly to tell him, very firmly, "Some things are best not discussed."

If however a guest brought up the latest royal scandal, the Queen Mother chose alcohol and flattery by selecting a topic that she knew interested the questioner, no matter how stultifying she found it personally, and gesturing subtly to a footman as she asked, "Do let's have another drink, I'm longing to hear about x" or "You must have another glass of wine, and won't you tell me all about y?"

One of the pleasures of growing older can be found in nostalgic reunions of friends and animated conversations beginning "Do you remember . . ." By the 1990s, there were few to whom the Queen Mother could say this. Excepting her sister-in-law Princess Alice, Duchess of Gloucester, who died aged 102 in 2004, Elizabeth had outlasted nearly all her contemporaries.

It would be wrong to characterise Elizabeth's final twelve years as solely defined by loss and unhappiness. There were still plenty of occasions when she greatly enjoyed life.

Spotting her equerry Colin Burgess riding a motorcycle, she called out, "I think perhaps it's a little too big for me!" or, as she was being driven through the Highlands in a Land Rover, "Come on, Colin, let's open her up a bit! Come on, Colin, put your foot down!" This might be followed by a firm order to halt if she spotted an open gate—"Stop the car! We must close that gate or the cows will escape." "We" lacked accuracy. She smiled encouragingly from inside the warm car as her driver or equerry got out to bolt the gates and save the local farmer's herd from wandering onto the road.

At her 101st birthday, she greeted well-wishers from a motorised buggy, beginning with a toddler who handed her a bunch of flowers and who introduced himself as "Aged Two." Forty-five minutes later, as the buggy trundled past the child again, the Queen Mother spotted him and waved, "Goodbye, Aged Two!" as she and her staff beetled back behind the gates of Clarence House.

One of her favourite guests was Nelson Mandela, the President of South Africa from 1994 to 1999. In 1996, President Mandela visited London and came to Clarence House for tea with the Queen Mother, where they chatted for hours longer than scheduled, before she attended a state banquet in his honour.

Her appetite and her sense of humour remained strong to the end. ("People say it's not good to eat butter. People say butter is bad for your heart. Well, I have eaten butter all my life and look at me.")

When a group of children were throwing rocks at cars on the Mall, the Queen Mother had her driver stop as she rolled down the window to chide the culprits. "Whatever will the American tourists think?" she asked them, before waving as she drove on.

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Prince William's favourite photograph of himself and his great-grandmother "is a picture of me aged about nine or ten, helping the Queen Mother up the steps of Windsor Castle. I remember the moment because she said to me, 'Keep doing that for people and you will go a long way in life.'" There are also adorable photographs of a young Prince Harry, in his suit and coat, holding an umbrella over his great-grandmother as they left church together.

In 2001, she threw a farewell lunch at Birkhall for Prince William before he started at St. Andrew's, the oldest university in Scotland. As the 101-year-old waved him off, she said, "Any good parties, invite me!"

"There was no way," Prince William said later. "I knew full well that if I invited her down, she would dance me under the table."