Simplify the following text for a Grade 8 native English-speaking person.
Original: In 2006 , Dunin published a book of 600 exercises in classical cryptography , which was published in the United States as The Mammoth Book of Secret Codes and Cryptograms , and in the UK as The Mammoth Book of Secret Code Puzzles .
Simplified: In 2006 , she wrote a book with hundreds of puzzles in it , called The Mammoth Book of Secret Codes and Cryptograms .