The Box-Car Children is a children's literary franchise originally created and written by American writer and first-grade school teacher, Gertrude Chandler Warner. Today, the series includes well over 100 titles. The series is aimed at readers in grades 2-6.

The original Boxcar Children tells the story of the four Alden children: Henry, Jessie, Violet, and Benny, who are orphans. One night, they take shelter in a bakery after buying some bread with the little cash they have. In exchange for allowing them to spend the night, they agree to help around the bakery. However, when they overhear the baker's plans to keep the older three siblings but to take Benny to an orphanage because he is too young, they flee.

Finding an abandoned boxcar, they start a new life of independence. Henry ends up working various odd jobs in a nearby city for a young doctor, Dr. Moore, in order to earn money for food. He also does gardening for the doctor's mother, Mrs. Moore. In one case, Mrs. Moore let him take home some parsnips and carrots he had picked because they were too small. The children's lives are pleasant and full of hard work until Violet becomes ill and they go to Dr. Moore for assistance.

Earlier in the novel, Dr. Moore read in the newspaper that a man named James Henry Alden was offering a $5,000 reward for anyone who located his four lost grandchildren. The children had run away because they thought their grandfather was cruel. After Dr. Moore takes the sick Violet and the other children to his house, he finally contacts James Alden. James arrives at Moore's house. Not wanting to frighten the children into running away again, their grandfather referred to himself as Mr. Henry. Not knowing that the man was their "cruel" grandfather, the children warm to his kindness and are surprised but delighted when Dr. Moore reveals to them that he is their grandfather. After moving in with their grandfather, James moves the boxcar to his backyard for their enjoyment.