I think that you mean "The Prince and the Pauper", a book written by Mark Twain.
Here is a review of that book, taken from the "Amazon" website....
"The Prince and the Pauper" by Mark Twain is a classic book and an absolute must-have. In this story of mistaken identity, Edward, the prince of Wales and the heir to the throne of England, switches places with Tom Canty, poor boy , forced to beg for living by his cruel, merciless father, also a beggar and a thief. What happens next? You are going to have to read the book to find out, and I promise, you will enjoy every single line of it. Mark Twain is one of the greatest writers, he has great sense of humour, that's why his books are so fun to read. "The Prince and the Pauper" is great for all ages. Children will enjoy this book as much as adults. I chose this particular edition of the book and I wasn't dissapointed. I LOVED IT! Great reading! "..............
http://www.amazon.com/gp/product/customer-reviews/0140367497/103-1784491-9333465