My book is ESIO TROT 

The book is about a man named Mr. Hoppy, who is single,

 but retires as a mechanic  and starts to be more alone than ever. 

Mr. Hoppy lived in an apartment and downstairs lived Mrs. Silver,

who is a widow who loves Alfie, her tortoise.

 Mr. Hoppy is in love with the lady, and he tries to get her by helping her to grow Alfie bigger.

Instead of growing Alfie bigger, he buys many tortoises and changes Alfie from his balcony. This makes Mrs. Silver very happy and they fall in love and marry. 

The writer is Roald Dahl is a famous English writer who writes children's stories,

 but it is difficult to know quite a lot of words for a child.