How many According Humphrey books are there?

There are 8 books in the "According to Humphrey" series by Betty Birney.

They are:

1. According to Humphrey

2. Humphrey's First Day at School

3. Humphrey's Big Day

4. Humphrey's Happy Holidays

5. Humphrey's First Summer

6. Humphrey's Big Surprise

7. Humphrey's Great Adventures

8. Humphrey's New Year's Eve