Education encompasses both the teaching and learning of knowledge, proper conduct, and technical competency. It thus focuses on the cultivation of skills, trades or professions, as well as mental, moral and aesthetic development.[1] Formal education consists of systematic instruction, teaching and training by teachers. This consists of the application of pedagogy and the development of curricula. In a liberal education tradition, teachers draw on many different disciplines for their lessons, including psychology, philosophy, linguistics, biology, and sociology. Teachers in specialized professions such as astrophysics, law, or zoology may teach only in a narrow area, usually as professors at institutions of higher learning. There is much specialist instruction in fields of trade for those who want specific skills, such as required to be a pilot, for example. Finally, there is an array of educational opportunity in the informal sphere- such as with museums and libraries. Informal education also includes knowledge and skills learned and refined during the course of life, including education that comes from experience in practicing a profession.