On the brink of manhood, Princes William, 19, and Harry, 16, grow closer as each forges his own identity, PEOPLE reports in its latest cover story. In looking at the two sons of Prince Charles and the late Princess Diana, the magazine also examines how the royal family circle has expanded to welcome their father's longtime love Camilla Parker Bowles, 54, who now has her own rooms at Charles's two main residences, St. James's Palace in London and Highgrove, his country estate in Gloucestershire. "They get on with her quite well, William perhaps slightly more than Harry," observes Brian Hoey, author of 15 books on the British royals. Hoey tells PEOPLE that when Charles is not present, the boys often chat with Camilla. Contrary to speculation that William has at times felt like a pawn in his father's campaign to burnish Camilla's public image, a source close to the royal family concurs that relations between Camilla and William are "social, warm and friendly." A family friend adds that the sons "want what is best for their father. She is what makes him happy, so they are happy with her."