George Berkeley (1685-1753) was an Irish philosopher whose primary philosophical achievement is the advancement of a theory he called 'immaterialism,' later referred to as 'subjective idealism' by others. This theory contends that individuals can only directly know sensations and ideas of objects, not abstractions such as 'matter.' Berkeley's most influential philosophical works include 'A Treatise Concerning the Principles of Human Knowledge' (1710) and 'Three Dialogues between Hylas and Philonous' (1713), where he famously argued, 'Esse est percipi' ('To be is to be perceived'). His 'An Essay Towards a New Theory of Vision' (1709) breaks from traditional understandings of visual perception by proposing that distance and three-dimensionality are learned rather than inherent to sight, a considerable contribution to empirical psychology and the philosophy of perception. Distinguished for his literary flair, Berkeley's style merges the precision of analytic argumentation with an almost poetic eloquence. His work remains a staple in the study of the early modern philosophy, and his ideas have significantly influenced the development of epistemology and metaphysics, resonating in contemporary discussions surrounding the philosophy of mind and the psychology of perception. In addition to his philosophical endeavors, Berkeley was also a bishop and an advocate for higher education in America, underlining his commitment to the betterment of society through education and moral improvement.