The fourth and final book in the modern classic, award-winning, bestselling One and Only series by superstar author Katherine Applegate, following Ivan on his most exciting adventure yet—parenthood. Ivan has been living in a wildlife sanctuary, with his friend Ruby next door in the elephant enclosure, frequent visits from his canine friend Bob, and his mate Kinyani by his side. And in the happiest turn of all, Ivan and Kinyani have welcomed a set of twins to their family! Ivan loves being a papa, even though it can be hard sometimes. But as he navigates the joys and challenges of parenthood, he can’t help but recall his life before the glass walls of the mall circus, his own childhood in the jungle—and his own twin. In the tradition of timeless classics like Charlotte’s Web and Stuart Little, the one and only Katherine Applegate has crafted a poignant, delightful, heartbreaking, unforgettable final foray into the world of Ivan, the world’s favorite silverback gorilla.