Gene Zion is the author of that all time favourite of young children, Harry the Dirty Dog. He wrote four books about Harry and other stories all illustrated by his then wife Margaret Bloy Graham.
Michael Morpurgo is a British author who writes for all age groups, but is a consummate storyteller for young readers from about 8 to 12 or 14. His novels 'sing', have worthwhile themes, but never preach. He has done picture books as well with such well known illustrators as Michael Foreman, Patrick Benson and Christian Birmingham. He was the third Children's Laureate, but has been credited with Ted Hughes with the idea of creating the position. It is hard to know which books to single out, so I have put in a favourite of mine, The Dancing Bear. I was very interested to read on his website which of his books were his favourites. Currently I know an eight year old boy who is on a mission to read all of Michael's books. I have found it a bit difficult to convince him that he should wait till he's older to read some of his titles!
Back to the USA for the third birthday. David Shannon is an author/ illustrator. He is well known for his series of books about David which originated from a book he made when he was about five years old called No David! and could only write those two words. As an adult he used the idea and redid the book and went on to do others about David. One of the kindergarten classes at my school are besotted with the David books and they borrow them frequently and for long periods of time so they can revisit them. They also like Shannon's pirate books that he has illustrated for Melinda Long. How I Became a Pirate has great lines about bedtime reading which I have used to great effect at parent nights to convince them of the virtues of bedtime reading.