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Primary Sources

This guide explains what primary sources are and demonstrates how to find them.

Research help at the Boston Public Library

If you have any questions about primary sources or research, you can ask the Boston Public Library for help!

By email:
By phone: Central - 617.536.5400 or your local branch 
In person: Central or your local branch


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Primary Sources
A primary source is an original item created at the time that is being studied. A primary source could include books, letters, contracts, paintings, government documents, and much more. We can learn a lot from primary sources about the time period they were created in and the people who created them. A primary resource is an original document, and no one has placed their own opinions or research upon it.


A digitized item is a high quality picture of the original item. Many places are digitizing collections, such as the Boston Public Library, Library of Congress, and many more. Many digitized collections are of old items, so they are out of copyright - which means they can be made freely available on the Internet. 

A transcription is written or typed text that is taken from another document. A transcription is usually a typed version of text that is
easier to read than the original source, such as a typed version of a hand-written letter.



Introduction to find primary sources

Japan Strikes All Over Pacific


Boston Globe, December 8, 1941, the day after the attack on Pearl Harbor.


Primary sources can be found in a variety of places; you just have to know where to look! Most of this guide focuses on digital collections because you can use these resources from anywhere with access to the Internet. Digital collections are images of the original primary source, which should be acceptable for most school and college research.

Below, you will find some links to websites with digital collections. The tabs contain significant eras in United States history. This is not all that is available, but it can be a starting off point. If you are researching an event that is not in this guide, use the links below to research through the Boston Public Library and other digital collections.

What is a primary source?

The difference between a primary resource and other resources is the primary resource is an item that was made at the same time period you are researching - such as photographs, letters, and newspaper articles. Most of the items you have encountered in your research were probably created after the event - journal articles, books, and websites.

To decide if an item is a primary source, ask yourself two questions:

What time period or event am I researching?

When was this item originally created?

If those two questions have the same answer, it’s a primary source!

If you still have questions about whether your resource is a primary source or not, you can always ask for help. If you need it for an assignment, you can ask your teacher or professor. You can also ask your school, academic, or public librarian for help.

Example identifying primary sources:

What time period am I researching? World War II, 1939-1945
When were my items created? 2014 and 1942

When Books Went to War
This book is NOT a primary source. It was published in 2014, not in the time period we are researching. It could be a great resource, but it is not a primary source.
"Books are weapons in the war on ideas" poster.
This poster is a primary source! It was created in 1942, which is in the time period we are researching.