This book is written by William Steig. This book is an award winning Children picture book.
Sylvester is a donkey and as the name mentioned it is a story of a donkey who collect the pebbles of unusual shape and color. Once when he was collecting he get a magic pebble that grants wishes.He aw ad he took it. At the same time a lion comes scares him. So he wish to become a rock to save himself from the lion and when he became rock the pebble fall off from him.
He was unable to change back as donkey form as the pebble must be in contact with the wish maker to work.
How he get the pebble? and How he came back too normal are the rest of the story which explains to us.It deals with the resulting aftermath.
It is a good picture story book to read for children and make them to think the imaginary world in their mind.