Primary source in the context of Physical observation

History is the systematic study of the past, focusing primarily on the human past. As an academic discipline, it analyses and interprets evidence to construct narratives about what happened and explain why it happened. Some theorists categorize history as a social science, while others see it as part of the humanities or consider it a hybrid discipline. Similar debates surround the purpose of history—for example, whether its main aim is theoretical, to uncover the truth, or practical, to learn lessons from the past. In a more general sense, the term history refers not to an academic field but to the past itself, times in the past, or to individual texts about the past.

Historical research relies on primary and secondary sources to reconstruct past events and validate interpretations. Source criticism is used to evaluate these sources, assessing their authenticity, content, and reliability. Historians strive to integrate the perspectives of several sources to develop a coherent narrative. Different schools of thought, such as positivism, the Annales school, Marxism, and postmodernism, have distinct methodological approaches.

In scholarship, a secondary source is a document or recording that relates or discusses information originally presented elsewhere. A secondary source contrasts with a primary, or original, source of the information being discussed. A primary source can be a person with direct knowledge of a situation or it may be a document created by such a person.

A secondary source is one that gives information about a primary source. In a secondary source, the original information is selected, modified and arranged in a suitable format. Secondary sources involve generalization, analysis, interpretation, or evaluation of the original information.

An official history is a work of history which is sponsored, authorised or endorsed by its subject. The term is most commonly used for histories which are produced for a government. The term also applies to commissions from non-state bodies including histories of commercial companies. An official biography (one written with the permission, cooperation and sometimes the participation of its subject or heirs) is an authorised biography.

Official histories frequently have the advantage that the author has had access to archives, been allowed to interview subjects and use other primary sources closed to independent historians. Because of the close relationship between author and subject, such works may be (or be perceived to be) partisan in tone and to lack historical objectivity. Such bias varies and some official histories have been called exercises in propaganda; in other cases the authors have retained a measure of independence.

Observation in the natural sciences refers to the active acquisition of information from a primary source. It involves the act of noticing or perceiving phenomena and gathering data based on direct engagement with the subject of study.

In living organisms, observation typically occurs through the senses. In science, it often extends beyond unaided perception, involving the use of scientific instruments to detect, measure, and record data. This enables the observation of phenomena not accessible to human senses alone.

An archive is an accumulation of historical records or materials, in any medium, or the physical facility in which they are located.

Archives contain primary source documents that have accumulated over the course of an individual or organization's lifetime, and are kept to show the history and function of that person or organization. Professional archivists and historians generally understand archives to be records that have been naturally and necessarily generated as a product of regular legal, commercial, administrative, or social activities. They have been metaphorically defined as "the secretions of an organism", and are distinguished from documents that have been consciously written or created to communicate a particular message to posterity.

A research library is a library that contains an in-depth collection of material on one or several subjects, including primary and secondary sources. Research libraries are established to meet research needs and, as such, are stocked with authentic materials with quality content. Research libraries are typically attached to academic or research institutions that specialize in that topic and serve members of that institution. Large university libraries are considered research libraries, and often contain many specialized branch research libraries. The libraries provide research materials for students and staff of these organizations to use and can also publish and carry literature produced by these institutions and make them available to others. Research libraries could also be accessible to members of the public who wish to gain in-depth knowledge on that particular topic.

Research libraries face a unique challenge of making research materials accessible and available to patrons. They also need to ensure there are no copyright-related issues with their materials, ensure that as many materials as possible are open access, and ensure all their materials are reliably sourced.

Samuel Pepys FRS (/ˈpiːps/ PEEPS; 23 February 1633 – 26 May 1703) was an English writer and Tory politician. He served as an official in the Navy Board and Member of Parliament, but is most remembered today for the diary he kept for almost a decade. Though he had no maritime experience, Pepys rose to be the Chief Secretary to the Admiralty under both Charles II and James II through patronage, diligence, and his talent for administration. His influence and reforms at the English Admiralty were important in the early professionalisation of the Royal Navy.

The detailed private diary that Pepys kept from 1660 until 1669 was first published in the 19th century and is one of the most important primary sources of the Stuart Restoration. It provides a combination of personal revelation and eyewitness accounts of great events, such as the Great Plague of London, the Second Anglo-Dutch War and the Great Fire of London.

Vuk Stefanović Karadžić (Serbian Cyrillic: Вук Стефановић Караџић, pronounced [ʋûːk stefǎːnoʋitɕ kâradʒitɕ]; 6 November 1787 (26 October OS) – 7 February 1864) was a Serbian philologist, anthropologist and linguist. He was one of the most important reformers of the modern Serbian language. Vuk Karadžić was a versatile scholar and the founder of several Serbian academic disciplines, with a significant contribution to historiography. For his collection and preservation of Serbian folktales, Encyclopædia Britannica labelled Karadžić "the father of Serbian folk-literature scholarship." He was also the author of the first Serbian dictionary in the new reformed language. In addition, he translated the New Testament into the reformed form of the Serbian spelling and language.

He was well known abroad and familiar to Jacob Grimm, Johann Wolfgang von Goethe and historian Leopold von Ranke. Karadžić was the primary source for Ranke's Die serbische Revolution ("The Serbian Revolution"), written in 1829.

Gnaeus Julius Agricola (/əˈɡrɪkələ/; 13 June 40 – 23 August 93) was a Roman general and politician responsible for much of the Roman conquest of Britain. Born to a political family of senatorial rank, Agricola began his military career as a military tribune under governor Gaius Suetonius Paulinus. In his subsequent career, he served in a variety of political positions in Rome. In 64, he was appointed quaestor in Asia province. Two years later, he was appointed Plebeian Tribune, and in 68, he was made praetor. During the Year of the Four Emperors in 69, he supported Vespasian, general of the Syrian army, in his bid for the throne.

When Vespasian became emperor, Agricola was made a patrician and appointed governor of Gallia Aquitania. In 77, he was made consul and governor of Britannia. As governor, he completed the conquest of what is today Wales and northern England, and led his army to the far north of Scotland, establishing forts across much of the lowlands. In 85, Agricola was recalled from Britain after an unusually lengthy service by Emperor Domitian. After his return, he retired from military and public life and died in 93. Most of what is known about Agricola and his governorship was written in the De vita et moribus Iulii Agricolae, a primary source, written by Tacitus, Agricola's son-in-law, and detailed archaeological evidence from northern Britain.

Anna Komnene (Greek: Ἄννα Κομνηνή, romanized: Ánna Komnēnḗ; 1 December 1083 – 1153), commonly Latinized as Anna Comnena, was a Byzantine Greek historian. She is the author of the Alexiad, an account of the reign of her father, Byzantine emperor Alexios I Komnenos. Her work constitutes the most important primary source of Byzantine history of the late 11th and early 12th centuries, as well as of the early Crusades. Although she is best known as the author of the Alexiad, Anna played an important part in the politics of the time and attempted to depose her brother John II Komnenos as emperor in favour of her husband, Nikephoros Bryennios the Younger.

At birth, Anna was betrothed to Constantine Doukas, and she grew up in his mother's household. She was well-educated in "Greek literature and history, philosophy, theology, mathematics, and medicine." Anna and Constantine were next in the line to throne until Anna's younger brother, John II Komnenos, became the heir in 1092. Constantine died around 1094, and Anna married Nikephoros Bryennios in 1097. The two had several children before Nikephoros' death around 1136.

Leopold von Ranke (21 December 1795 – 23 May 1886) was a German historian and a founder of modern source-based history. He was able to implement the seminar teaching method in his classroom and focused on archival research and the analysis of historical documents. Building on the methods of the Göttingen school of history, he was the first to establish a historical seminar. Ranke set the standards for much of later historical writing, introducing such ideas as reliance on primary sources (empiricism), an emphasis on narrative history and especially international politics (Außenpolitik). He was ennobled in 1865, with the addition of a "von" to his name.

Ranke also had a great influence on Western historiography and is considered a symbol of the quality of 19th century German historical studies. Ranke, influenced by Barthold Georg Niebuhr, was very talented in constructing narratives without exceeding the limits of historical evidence. His critics have noted the influence of Lutheranism in guiding his work, especially his belief that God's actions were manifest in the lives of men and history, a viewpoint that shaped his ideas that the German Empire was a manifestation of God's intent.

A review article is a journal article that summarizes the current state of understanding on a topic within a certain discipline. A review article is generally considered a secondary source since it may analyze and discuss the method and conclusions in previously published studies. It resembles a survey article or, in news publishing, overview article, which also surveys and summarizes previously published primary and secondary sources, instead of reporting new facts and results. Survey articles are however considered tertiary sources, since they do not provide additional analysis and synthesis of new conclusions. A review of such sources is often referred to as a tertiary review.

Academic publications that specialize in review articles are known as review journals. Review journals have their own requirements for the review articles they accept, so review articles may vary slightly depending on the journal they are being submitted to.