Computer science is the study of computers and their associated phenomena, but what are ‘computers’ and ‘associated phenomena’? ‘The “stuff” of computing’ explains that a computer is an automaton—an artefact designed to simulate and imitate certain kinds of human thought processes. The fundamental stuff of computer science is information and an alternative term for computing is ‘information processing’. This information can be ‘meaningless’ or ‘meaningful’. The unit of information in information theory is the bit (short for ‘binary digit’) and a byte consists of eight bits. But is information knowledge or data? Information, knowledge, and data can all be expressed by symbol structures and so computing is symbol processing.