Clifford the Big Red Dog is an eponymously titled American children's book series about a giant red dog named Clifford. It was first published in 1963 and was written by Norman Bridwell (1928–2014). The series helped establish Scholastic as a premier publishing company, and Clifford himself is Scholastic's official mascot.
- Clifford: a male red dog whose appearance, disposition, and behavior are based on a giant "all-around" dog. Clifford is shy, gentle, friendly, loyal, lovable, clumsy, well-meaning and helpful. He sometimes gets into trouble because of his size or is tempted into trouble by his friends and those he meets. His size, like giants in medieval legends, is inconsistent—he is often shown as being about 25 feet tall from paws to head, but can appear far larger: For example, in one episode of the show, he removes the top of a lighthouse and swims out with it to guide a ferry through the fog to the dock. The character's name is based on the imaginary childhood friend of creator Norman Bridwell's wife. He originally wanted to name him "Tiny", but his wife persuaded him otherwise. His owner is Emily Elizabeth, to whom he is devoted. He has a mother, two brothers, and two sisters. His character was created when an editor at Harper & Row advised Bridwell to write a story to go along with one of his pictures. She picked out his sketch of a baby girl and a horse-sized bloodhound and casually said, "There might be a story in this," Bridwell remembers.
- Emily Elizabeth: Clifford's owner. A friendly, curious, and helpful eight-year-old girl. She is frequently portrayed riding on his bare back. She is the best skater on the island, and is also very good at soccer. She was named for creator Norman Bridwell's daughter and based on the imaginary adventures of Bridwell's wife. The TV series adaptation gives her a surname, Emily Elizabeth Howard, and changes the background, with her receiving Clifford as a surprise present on her 6th birthday instead of picking him out as a Christmas present.