Ruby is a high-level, fully object-oriented programming (OOP) language. It is very powerful and relatively easy to learn, read, and maintain. Sams Teach Yourself Ruby in 21 Days provides the best introduction to this language and addresses one of the key constraints it faces: "The paucity of quality English-language documentation is one of the few things holding Ruby back from widespread adoption," according to Dr. Curtis Clifton of Iowa State University's Department of Graduate Computer Science.