Who is Algernon in Flowers for ALgernon?

Young Charlie had a crush on a classmate named Harriet at PS 13. Charlie asked Hymie Roth to write a love letter, so that Charlie could present it to Harriet with a golden locket that he found in the street. Instead of recording Charlie's innocent love note, Hymie wrote an obscene message and signed Charlie's name to it. Harriet's furious big brothers beat Charlie up and he was forced to change schools.