Kate Middleton Poised to Retreat From Public Life Again

Kate Middleton may have only just made her return to the public eye, but royal watchers shouldn't expect to see her again anytime soon. Following her Wimbledon appearance alongside 9-year-old daughter Princess Charlotte and sister Pippa Middleton earlier this month, the Princess of Wales is reportedly poised to once again retreat from public life amid her cancer treatment .

The Sunday, July 22 outing, which marked only her second public event of the year, likely marked Middleton's final public outing before she retreats for "a quiet summer," Robert Jobson, author of the new book Catherine, the Princess of Wales: A Biography of the Future Queen, told PEOPLE . Jobson noted that while the 42-year-old royal "used to live her life by the calendar," she is now "living her life, and the calendar comes in after."

Jobson said Middleton's recent cancer diagnosis has given her a new outlook on life, telling the outlet, "when you have had an experience like this, it changes your perspective and the order of things." Middleton announced her cancer diagnosis in March after undergoing a planned abdominal surgery in January . She largely remained out of the spotlight until June, when she joined other members of the British royal family for the annual Trooping the Colour.

In a health update at the time , the princess said she was "making good progress" and her treatment "is ongoing and will be for a few more months." Although she said she was "starting to do a little work from home" and was hoping "to join a few public engagements over the summer," she made clear that her appearance at Trooping the Colour did not signal a return to public life, acknowledging that she's "not out of the woods yet." She also said that amid her treatment, she was choosing to "engage with school life, spend personal time on the things that give me energy and positivity."

According to Jobson, Middleton and her family - husband Prince William and their three children, Charlotte, 9, Prince George, 11 , and Prince Louis, 6 - are expected to spend the summer at Amner Hall, their country home. The family will reportedly enjoy "a late-summer star" hosted by King Charles, 75, at Balmoral Castle. Jobson said that during this time, Middleton "won't have to be on center stage. Being with her family and just being herself will give her energy. There will be plenty of time to focus on her recovery."