Personal texts--diaries, memoirs, letters, autobiographies, and papers--usually make excellent primary sources because they were written by a historical person you're studying.
Personal texts are scattered throughout the internet, in databases, and on the shelves of the UA Libraries. Here are some techniques for locating diaries, letters, and other primary sources using Scout, Google, or Classic Catalog:
-"knits together more than 400 sources of diaries, letters, and memoirs, to provide fast access to thousands of views on almost every aspect of the war."
North American Women's Letters and Diaries--"largest collection of women's diaries and letters ever assembled, covers colonial times--1950."
The Sixties: Primary Documents and Personal Narratives, 1960-1974--"this collection of primary resources documents the history, culture, and politics of the 1960s and early 1970s. Included are diaries, letters, autobiographies and other memoirs."
offers the papers of George Washington, John Adams, Thomas Jefferson, James Madision, Dolly Madision, Alexander Hamilton, John Marshall, and more.
Here's the papers (some in print at Gorgas Library, some electronic) of a few movers and shakers of the 20th century:
You can now find audio recordings for some twentieth century figures for free on the internet. For example, please see nixontapes.org to hear telephone conversations between Richard Nixon and others.