What is so unusual is that the drawings and the lettering are anamorphic, and can only be viewed non-distorted when reflected in a cylindrical mirror.
The book is out of print, but new copies came with two sheets of mirror paper for the reader to roll into a cylinder. I was lucky enough to find a used copy that still had the mirror paper tucked inside the book.
Here is the capital Q page viewed with the naked eye.
Roll the mirror paper into a tube, place the tube over the (non-anamorphic) drawing of the Quince, and see the Q and the Queen magically appear as they should.
One half of the book is capital letters, featuring objects that begin with the letter, the other half is lower case letters, featuring animals that begin with the letter.
Here is k for kangaroo:
The cover is drawn anamorphically as well. Here it is viewed in the mirror paper:
This book was a collaboration between Japanese artist Mitsumasa Anno and his son, Masaichiro Anno. The son did the lettering, while the father created the paintings. Originally published in 1980 in Japan, the book was published in the United States by Philomel Books in 1981.
edited: This book also has instructions for creating your own anamorphic drawings, complete with graphs to help the experimenting artist along.