Simplify the following text for a Grade 8 native English-speaking person.
Original: After assorted work on posters for London and British Transport and animated films , he began his writing career in 1963 with the book Borka : The Adventures of a Goose With No Feathers which won the 1963 Kate Greenaway Medal .
Simplified: He has won many awards including the Kate Greenaway Medal in 1963 for his book called Borka : The Adventures of a Goose With No Feathers