1. Are You There God? It's Me, Margaret (1970) - Fudge isn't born yet, but Peter is the main character.
2. Tales of a Fourth Grade Nothing (1972) - This is the first book where Fudge is the main character, though Peter is still a primary character.
3. Otherwise Known as Sheila the Great (1972) - Peter is again the main character, and Fudge is a supporting character.
4. Superfudge (1980) - Fudge is the main character, and Peter is a supporting character.
5. Fudge-a-mania (1990) - Fudge is the main character, and Peter is a supporting character.
It's worth noting that even though the books are chronological, they can be enjoyed in any order. The "Fudge" books are full of humor and relatable situations for young readers.