The nature of nursing and the need for knowledge distinct from medicine was first spoken of by Florence Nightingale in 1859 Her notions may be regarded as the earliest formations of nursing as a discipline Since that time there has been substantial effort committed to the development of a distinct theory base for nursing Increased interest in nursing's unique body of knowledge has been particularly evident in the last decade, as seen by the growth in research undertaken from a nursing perspective, and by the numbers of publications which focus on the nature of knowledge and theory in nursing These efforts have served not only to advance the discipline of nursing but also to challenge all nurses to articulate for themselves the theoretical foundations of their own practice The main thesis of this paper is that nursing is an evolving discipline Aspects of its evolution will be discussed using the four characteristics of a discipline, domain, syntax, history, and output of knowledge