Since the 1950s, the concept of information has acquired a strikingly prominent role in many parts of biology. This enthusiasm extends far beyond domains where the concept might seem to have an obvious application, such as the biological study of perception, cognition, and language, and now reaches into the most basic parts of biological theory. Hormones and other cellular products through which physiological systems are regulated are typically described as signals.  Descriptions of how genes play their causal role in metabolic processes and development are routinely given in terms of “transcription”, “translation”, and “editing”. The most general term used for the processes by which genes exert their effects is “gene expression”. The fates of cells in a developing organism are explained in terms of their processing of “positional information” given to them from surrounding cells and other factors. Many biologists think of the developmental processes by which organisms progress from egg to adult in terms of the execution of a “developmental program”. Other biologists have argued for a pivotal role for information in evolution rather than development: John Maynard Smith and Eors Szathmáry (for example) suggest that major transitions in evolution depend on expansions in the amount and accuracy with which information is transmitted across generations. And some have argued that we can only understand the evolutionary role of genes by recognizing an informational “domain” that exists alongside the domain of matter and energy. 