Primary sources are the core of historical research. Broadly defined, they include all materials produced by people. They include obvious sources like diaries, letters, speeches, government documents, contemporary publications, laws, police and court records, maps, newspapers, and photographs. Remember, however, that there are other primary sources too: public opinion polls, telephone directories, coins, inscriptions, advertisements, business records, works of art, city directories, poetry, music, buildings, statues, organizational minutes, railroad schedules, birth, marriage, and death records, novels, political debates, films, furniture, and tombstones. This list is far from exhaustive.
Like every human work, however, each primary source has a particular perspective, based on the goals and background of its creator(s). The historian, when analyzing and writing about the past, must always consider these various perspectives. See the link to the right on What You Need to Know for more on using primary sources.
One of the advantages of the rise of the Internet has been greater accessibility to primary source collections. See the links below for a list of links to useful online primary source collections of particular interest to historians.