Drawn from major repositories throughout the South, these primary documents are rich resources for scholars. They open new directions for research on plantations as economic and social systems, values and culture among the southern elite, slavery and emancipation, women's roles, life among the yeoman class, marketing of staple crops, national politics, southern politics, the Civil War, and myriad other aspects of the antebellum period. Because the plantation was a commercial enterprise, record keeping was essential. Many planters kept journals, crop books, overseers' journals, and account books in remarkable detail. Family members often kept personal diaries and corresponded extensively with friends and relatives near and far. Series L, Part 4 provides voluminous documentation of Piedmont Virginia in the 19th century. These collections are particularly valuable sources for the study of slavery and the medical treatment of slaves. One collection even includes an index of items referring to slaves and slavery. The Austin-Twyman papers form the bulk of this part and are a rich but rarely explored source on slavery in 19th-century Virginia. There are seven slave letters in the collection, including one written by a woman to her son, Beverley. Other items tell more about Beverley's life. There are also documents on the care of a child while the mother, a slave, worked in the field; the sale of a child; slave hire agreements; permission for slaves to marry off the plantation; qualms about slave ownership; and profits or losses sustained through slavery in agriculture and industry.