Nursing’s theoretical knowledge has a rich heritage in its development, dating back to the writings of Florence Nightingale and emanating from the work of many nursing scholars of the past three decades. Although there is a continuing debate about whether nursing theories, as they exist, are mature enough or rigorously developed, nursing theories, large and small, have become the cornerstone for understanding and guiding nursing practice in the current decade. However, there are many questions about nursing theories and their contents that trouble students of nursing, whether they are undergraduate or graduate students or practicing nurses.