In the first and only title to win both the prestigious Kate Greenaway and Caldecott Medal, and by the illustrator of the bestselling I Want My Hat Back and Sam and Dave Dig a Hole, a tiny fish proudly wears a blue top hat. It fits him perfectly. Problem is, trouble could be following close behind...So it's a good thing that the enormous fish he took it from won't wake up. And even if he does, it's not as though he'll ever know what happened, right? With so many emotions conveyed in just the glint of an eye, visual humour swims to the fore in this thrillingly original, perfectly-paced cautionary tale.

《IWant My Hat Back》推出以来，便深获小朋友的喜爱，除了荣登纽约时报畅销书排行榜外，也获得多项大奖肯定。延续先前的热潮，作者Jon Klassen推出续作《This is Not My Hat》，不过这次一改先前明亮基调，在用色上以深色为基底制造反差，更图显各个角色的份量。故事发生在海底，一只大鱼正呼呼大睡，一只小鱼神色自若地从大鱼那里偷走了一顶蓝色的帽子，但他毫不掩饰，边游边向路过的海底生物说：「这顶帽子不是我的，我偷了它。」小鱼自在地向前游，却没有意识到大鱼正在后头静静的跟着他……作者留下了一个开放式的结尾，让小朋友在每次阅读后发挥自己的想象力，而这只小鱼的命运于是有了各种可能性。