You may have noticed an interesting phenomenon lately in the book business, especially in the publication of illustrated books for children.An increasing number of entertainers and celebrities have become writers, including the likes of Madonna, Jay Leno, Jerry Seinfeld and Julie Andrews. Include in this mix John Travolta.So it should come as no surprise that Chicago’s Denise McGowan Tracy, the former entertainment director for Navy Pier and founder of DMT Entertainment, would write one too. McGowan Tracy — the host of …