Aristotle's writings were preserved by his student Theophrastus, his successor as leader of the Peripatetic School. Theophrastus' pupil Neleus and his heirs concealed the books in a vault to protect them from theft, but they were damaged by dampness, moths and worms. The books were found around 100 BC by Apellicon, who brought them to Rome. In Rome, scholars took interest in the works and prepared new editions of them. The writings of Aristotle that we have today are based on this collection. Overall, Aristotle wrote three types of works: dialogues or other works of a popular character, collections of scientific data and observations, and systematic treatises. His philosophy can be divided into four main areas: 1) Logic; 2) Theoretical Philosophy, including Metaphysics, Physics and Mathematics; 3) Practical Philosophy, such as Ethics and Politics; and 4) Poetical Philosophy, covering the study of poetry and the fine arts.