Nursing is a profession within the health care sector focused on the care of individuals, families, and communities so they may attain, maintain, or recover optimal health and quality of life.
 
Nurses may be differentiated from other health care providers by their approach to patient care, training, and scope of practice. Nurses practice in a wide diversity of practice areas with a different scope of practice and level of prescriber authority in each. Many nurses provide care within the ordering scope of physicians, and this traditional role has come to shape the historic public image of nurses as care providers. However, nurses are permitted by most jurisdictions to practice independently in a variety of settings depending on training level. In the postwar period, nurse education has undergone a process of diversification towards advanced and specialized credentials, and many of the traditional regulations and provider roles are changing.
 
The American Nurses Association (ANA) states nursing is the protection, promotion, and optimization of health and abilities, prevention of illness and injury, alleviation of suffering through the diagnosis and treatment of human response, and advocacy in the care of individuals, families, communities, and populations.

Before the foundation of modern nursing, nuns and the military often provided nursing-like services.
 
The religious and military roots of modern nursing remain in evidence today in many countries, for example in the United Kingdom, senior female nurses are known as sisters. Nurses execute the "Orders" of other health care professionals in addition to being responsible for their own practice.
 
The first known Nurse, Phoebe, was mentioned in Romans 16:1. During the early years of the Christian Church, St. Paul sent a deaconess Phoebe to Rome as the first visiting nurse. She took care of both women and men.
 
The Crimean War was a significant development in nursing history, when English nurse Florence Nightingale, laid the foundations of professional nursing with the principles summarised in the book Notes on Nursing.
 
Other important nurses in the development of the profession include:
 Mary Seacole, who also worked as a nurse in the Crimea
 Agnes Elizabeth Jones and Linda Richards, who established quality nursing schools in the USA and Japan; Linda Richards was officially America's first professionally trained nurse, graduating in 1873 from the New England Hospital for Women and Children in Boston
 Clarissa Harlowe "Clara" Barton, a pioneer American teacher, patent clerk, nurse, and humanitarian, and the founder of the American Red Cross.
 
New Zealand was the first country to regulate nurses nationally, with adoption of the Nurses Registration Act on the 12 September 1901. It was here in New Zealand that Ellen Dougherty became the first registered nurse. North Carolina was the first state in the United States to pass a nursing license law in 1903. In the 1990s nurses became able to prescribe medications, order diagnostic and pathology tests and refer patients to other health professionals as needed. Reference Potter & Perrys (2009)
 
Nurses in the United States Army actually started during the Revolutionary War when a general suggested to George Washington that the he needed female nurses "to attend the sick and obey the matron's orders. In July 1775, a plan was submitted to the Second Continental Congress that provided one nurse for every ten patients and provided that a matron be allotted to every hundred sick or wounded".
 
Nurses have experienced difficulty with the hierarchy in medicine that has resulted in an impression that nurses' primary purpose is to follow the direction of physicians. This tendency is certainly not observed in Nightingale's Notes on Nursing, where the physicians are mentioned relatively infrequently, and often in critical tones—particularly relating to bedside manner.
 
In the early 1900s, the autonomous, nursing-controlled, Nightingale era schools came to an end – schools became controlled by hospitals, and formal "book learning" was discouraged. Hospitals and physicians saw women in nursing as a source of free or inexpensive labor. Exploitation was not uncommon by nurse’s employers, physicians and educational providers. Nursing practice was controlled by medicine.
 
The modern era has seen the development of nursing degrees and nursing has numerous journals to broaden the knowledge base of the profession. Nurses are often in key management roles within health services and hold research posts at universities.

Before the late 19th century, and into the early 20th century, women doing nursing work were generally members of religious orders or were effectively domestic servants, with the same lowly social status, caring for the sick either in private homes or at charity hospitals serving the poor. Florence Nightingale's efforts to improve nursing standards in the mid-nineteenth century increased interest in occupational improvements that would benefit patients, with particular importance given to military settings. In 1860, Florence Nightingale's work resulted in Queen Victoria's order for a hospital to be built to train Army nurses and surgeons, the Royal Victoria Hospital. The hospital opened in 1863 in Netley and admitted and cared for military patients. Beginning in 1866, nurses were formally appointed to Military General Hospitals. The Army Nursing Service (ANS) oversaw the work of the nurses starting in 1881. These military nurses were sent overseas beginning with the First Boer War (often called Zulu War) from 1879 to 1881. They were also dispatched to serve during the Egyptian Campaign in 1882 and the Sudan War of 1883 to 1884. During the Sudan War members of the Army Nursing Service nursed in hospital ships on the Nile as well as the Citadel in Cairo. Almost 2000 nurses served during the second Boer War, the Anglo-Boer War of 1899 to 1902, alongside nurses who were part of the colonial armies of Australia, Canada and New Zealand. They served in tented field hospitals. 23 Army Nursing sisters from Britain lost their lives from disease outbreaks.
 
Sporadic progress was made on several continents, where medical pioneers established formal nursing schools. But even as late as the 1870s, "women working in North American urban hospitals typically were untrained, working class, and accorded lowly status by both the medical profession they supported and society at large". Nursing had the same status in Great Britain and continental Europe before World War I.

Nursing as a profession
The authority for the practice of nursing is based upon a social contract that delineates professional rights and responsibilities as well as mechanisms for public accountability. In almost all countries, nursing practice is defined and governed by law, and entrance to the profession is regulated at the national or state level.
 
The aim of the nursing community worldwide is for its professionals to ensure quality care for all, while maintaining their credentials, code of ethics, standards, and competencies, and continuing their education. There are a number of educational paths to becoming a professional nurse, which vary greatly worldwide; all involve extensive study of nursing theory and practice as well as training in clinical skills.
 
Nurses care for individuals of all ages and cultural backgrounds who are healthy and ill in a holistic manner based on the individual's physical, emotional, psychological, intellectual, social, and spiritual needs. The profession combines physical science, social science, nursing theory, and technology in caring for those individuals.
 
In order to work in the nursing profession, all nurses hold one or more credentials depending on their scope of practice and education. A Licensed practical nurse (LPN) (also referred to as a Licensed vocational nurse, Registered practical nurse, Enrolled nurse, and State enrolled nurse) works independently or with a Registered nurse (RN). The most significant differentiation between an LPN and RN is found in the requirements for entry to practice, which determines entitlement for their scope of practice. For example, Canada requires a bachelors degree for the RN and a two-year diploma for the LPN. A Registered nurse (RN) provides scientific, psychological, and technological knowledge in the care of patients and families in many health care settings. Registered nurses may earn additional credentials or degrees. In the USA, multiple educational paths will qualify a candidate to sit for the licensure examination as a registered nurse. The ADN is awarded to the nurse who has completed a two-year undergraduate academic degree awarded by community colleges, junior colleges, technical colleges, and bachelor's degree-granting colleges and universities upon completion of a course of study usually lasting two years. The BSN is awarded to the nurse who has earned an American four-year academic degree in the science and principles of nursing, granted by a tertiary education university or similarly accredited school. After completing either the LPN or either RN education programs in the USA, graduates are eligible to sit for the a licensing examination to become a nurse, the passing of which is required for the nursing license.
 
RNs may also pursue different roles as advanced practice registered nurses.
 
Nurses may follow their personal and professional interests by working with any group of people, in any setting, at any time. Some nurses follow the traditional role of working in a hospital setting.
 
Around the world, nurses have been traditionally female. Despite equal opportunity legislation, nursing has continued to be a female-dominated profession. For instance, the male-to-female ratio of nurses is approximately 1:19 in Canada and America. This ratio is represented around the world. Notable exceptions include Francophone Africa, which includes the countries of Benin, Burkina Faso, Cameroon, Chad, Congo, Côte d'Ivoire, the Democratic Republic of Congo, Djibouti, Guinea, Gabon, Mali, Mauritania, Niger, Rwanda, Senegal, and Togo, which all have more male than female nurses. In Europe, in countries such as Spain, Portugal, Czechoslovakia, and Italy, over 20% of nurses are male.
 
Nursing theory and process
Nursing practice is the actual provision of nursing care. In providing care, nurses implement the nursing care plan using the nursing process. This is based around a specific nursing theory which is selected based on the care setting and population served. In providing nursing care, the nurse uses both nursing theory and best practice derived from nursing research.
 
In general terms, the nursing process is the method used to assess and diagnose needs, plan outcomes and interventions, implement interventions, and evaluate the outcomes of the care provided. Like other disciplines, the profession has developed different theories derived from sometimes diverse philosophical beliefs and paradigms or worldviews to help nurses direct their activities to accomplish specific goals.