Development for The Lightning Thief began when author Rick Riordan made up stories for his son Haley, who had been diagnosed with ADHD and dyslexia. His son had been studying Greek mythology in second grade and asked that his father come up with bedtime stories based on Greek myths. Riordan had been a Greek mythology teacher in middle school for many years and was able to remember enough stories to please his son. Soon Riordan ran out of myths and his son requested that Riordan make new ones using the characters from Greek myths with a new twist. Riordan created the fictional character Percy Jackson and his travels across the United States to recover Zeus's lightning bolt. In his new story, Riordan made ADHD and dyslexia part of a demigod's powers - respectively, heightened battle reflexes and a brain wired to read ancient Greek rather than English. After Riordan finished telling the story his son asked that his dad write a book based on Percy's adventures, and he did.
While he gave his manuscript to his agent and editor to review, Riordan took his book to a group of middle schoolers to critique. With their help, he came up with the name of the book and invented Percy's magic sword. Riordan first sent out the manuscript for The Lightning Thief under a pseudonym, as he did not want to rely on anyone in the publisher industry, who would have known him through his previous work. After many rejections, an agent picked up the manuscript as she liked its premise. In 2004 the book was sold to Miramax Books for enough money that Riordan could quit his job to focus on writing. The book has since been released in multiple versions (including hardcover, paperback, and audio editions) and has been translated and published all over the world.