It's vacation time, so Emily has to write to her teacher to help when she discovers a blue whale living in her pond. Mr. Blueberry answers that she must be mistaken, because whales live in the ocean, not in ponds.

Throughout the summer, Emily and Mr. Blueberry exchange letters, until Emily has a happy surprise to share with her teacher. In the process, Emily learns a lot about whales. And Mr. Blueberry leans even more about imagination, faith, and love.
Dear Mr. Blueberry》就从一个小女孩Emily的奇想开始,Emily写信给Mr.Blueberry 说她非常喜欢蓝鲸,而且她昨晚在家里的池塘发现一只蓝鲸,她想问老师关于蓝鲸的知识. 然后,老师回信了,告诉她鲸鱼不可能住在池塘,因为鲸鱼活在咸咸的海水里. Emily又写信给老师,说她每天早餐前会在水池里加盐,她觉得鲸鱼好像觉得好多了. Emily不断地写信问,老师则不断地”纠正”Emily的观念.,但是Emily却不断地写信,开心地告诉老师她和鲸鱼的友情,越来越好,蓝鲸甚至愿意让她碰碰它的头. ......
有一天,鲸鱼不见了,Emily写信告诉Mr Blueberry,她有些伤心,不过老师还是以严肃的口吻告诉小女孩鲸鱼不可能住在水池里.
但是,有一天Emily很开心地写了一封信给老师:

小女孩最后还是保有了自己的想像,没又被大人教化成为严肃只拥有知识而没有想像的”乖小孩”.
而书中除了知识性的书信格式与自然生态的学习,两边书信的往来,大人的"合理世界"与小孩的奇想世界交错着,正好让阅读者检是自己的内在思维,我在阅读的过程中,一直很好奇最后到底会如何?最后那封信让我有一颗甜美的心情阖上这本书.

Dear Mr.Blueberry,
It’s been the happiest day! I went to the beach and you’ll never guess,
But I saw Arthur ! I called to him and he smiled.
I knew it was Arthur because he let me stroke his head.
I gave him some of my sandwich…..and then we said good-bye.
I should that I loved him very much
and , I hope you don’t mind ,I said you loved him,too.
Love
Emily(and Arthur)