Originally written by Norman Bridwell, Clifford the Big Red Dog was published by Scholastic in book form and in 2000 was adapted to television format.  It first aired from 2000 to 2003.  John Ritter provided the voice of Clifford.  The show was one of several PBS Kids shows that was designed to teach life lessons to their viewers. The television show followed the life of a tiny puppy that was given to a young girl which lived in the city. 

Before long, and because of how much the little girl loved Clifford, he grew to be over 25 feet tall, which caused the girl and her family to move away from the city to Birdwell Island (an anagram of Norman Bridwell, the author of the Clifford's series).  Clifford had many friends, among them: Emily Elizabeth, Charley, Samuel, and Mr. Howard (Emily Elizabeth's father). 

Trivia :  The voice of Clifford, John Ritter, originally starred in Three's Company (1977-1984) and 8 Simple Rules for Dating My Teenage Daughter (2002-2003).