This is a substantial revision of the Stanford Encyclopedia of Philosophy entry on 'information' and useful as a reference to what is a central concept in information technology and online learning. The important distinction made in this article is between 'qualitative' (or 'semantic') theories of information, and 'quantitative' theories. The latter are concepts used in fields like data transmission (where 'information' would be what is encoded in the data stream). The former are more commonly associated with knowledge and belief (and therefore learning). More. My own use of the term is generally semantic, and subjectively oriented, where (with Dretske, 1981) the quantity of information in a transmission is the reduction of uncertainty produced in the receiver by the transmission.