Henry James Alden is one of the Boxcar Children. He is 14 years old, thus making him the oldest of the group. He is in all of the mystery stories. He thinks of all the possibilities when they are trying to solve a mystery. He is a very fast runner.
He loves all of his siblings and works to get money to buy food to keep them alive. By the ninth book he is in college, and by the nineteenth he is getting ready to graduate from Adam's College. His favorite color is green, and he has a large blue car. There are hints throughout the book that his grandfather is grooming him to take over the family business. He (and Jessie) are also shown to be fluent in French.
Note: in the later books (written after Gertrude Warner's death) he is de-aged to 14 again.