For historians who use letters and diaries, the pleasures of reading them translate into specific reasons for why they are valuable windows for looking into the past. Both kinds of personal texts rely on narrative, or storytelling, something which gives historians a useful, inspiring, and sometimes challenging threshold for the story they want to tell. Too, most personal texts have a certain open, candid quality which contrasts with the highly conceptualized and self-protective language of more "official" documents. Finally, although only literate people kept diaries and exchanged letters, both forms were important to a wide variety of people in the past – rich and not-so-rich, old and young, women and men – and thus diaries and letters are among the most democratic of historical sources.

With these things in mind, and before we consider particular strategies for reading personal letters and diaries, it is helpful to recall how both forms take their shape from "public" or cultural conventions of expression, and from the aims of each individual diarist or letter writer. (We will be looking mostly at nineteenth century texts, as they set the tone for modern letters and diaries, and yet they also retained elements of earlier forms.) Each letter or diary is the result of how a particular writer modified or "bent" the conventions at hand. In this sense, the conventions might be likened to a script and each diary or letter to an actual performance. The historical richness of these texts is found precisely in the friction between the general form available to all writers and individuals’ use of it for their own purposes. For example, lovers courting each other in the 1850s wrote love letters which tracked along certain expressive paths. They employed certain forms of address, wrote on certain topics, and flirted in certain ways. In a very real sense, they "fell in love" in part by inscribing identities for themselves as desirable lovers, showing that they knew the "rules" of the game. In fact, it was common for a lover to take pleasure in her beloved’s letter (and to share it with her friends) simply because it followed good form. Parents did much the same thing with the dutiful letters their children wrote to them, and even business letters followed certain expected forms which smoothed the path for financial transactions. Many diarists, too, acknowledged the importance of form by expressing the hope that their attempts at journalizing would live up to the expressive potential of diary-keeping. In all these ways, the shared attention to form sheds light on shared historical experience.

Moreover, letters and diaries each are given common shape by widely shared life events. In family after family, letters tend to cluster around certain key events: births, separations over time and distance, sickness and health, courtships and marriages, and deaths. Diarists, too, are apt to take up their pen in the face of life transitions, mapping the course of the ordinary or, quite differently, reporting unusual events, such as a long journey or the coming of war. These latter "diaries of situation," as Steven Kagle calls them, sometimes end when the situation resolves. However, in other instances, the diarist extends her writing into a life-long practice, caught by the pleasure of recording her days. As people wrote about events – meeting someone new, the coming of a storm, a death in the family – they inevitably wrote about their relationships with others. And writing to or about others, they wrote themselves anew each time. Although they may not have thought about it this way as they wrote, they nonetheless were making for themselves a personal presence in the wider world of the written word typical of their time and place.*

Thus, the historical value of reading diaries and letters involves understanding the significance of how individual writers employed, experimented with, or altered the conventional forms alive in their time. Perhaps more than any other kind of historical text, the personal writing we are considering reveals how people both embraced and resisted the time and place in which they lived. Their personal motives for employing either form – the emotional and intellectual energy infusing the form with life each time it is written with a new subjectivity – suggest much about how people in the past made their cultures, but made them from the materials at hand.

Thus, John Mack Faragher has shown how American women moving West in the nineteenth century wrote conventional letters home, filled with good wishes and narrative descriptions of travel, but also infused them with longing and loss beyond what we might expect. Judy Litoff and David Smith similarly have shown the range of feeling and depth of commitment in the letters of World War II families, and Elizabeth Hampsten has sounded the depths of midwestern farm women’s personal writing, rich with the desire to tell, yet paradoxically inscribed "read this only to yourself." Particular letters and diaries have changed or added to our way of looking at aspects of the past. Publication of the letters of Abigail and John Adams, for instance, helped us to understand Abigail’s importance as an intellectual influence on her better-known President husband, as well as revealing that domestic life was a thoroughly political realm in Revolutionary America. The diary of an "ordinary" midwife, Martha Ballard, permitted Laurel Thatcher Ulrich to argue for the importance of women’s medical work in colonial American communities, and how this world helped shape ideas about – and the practice of – care-giving, science, and community values among New Englanders.