Incunabula (incunabulum in the singular) is Latin for cradle or swaddling cloth and in this context alludes to the "infancy of printing." Incunabula refers to those early books which were printed between 1450 and 1501. If one follows conventional periodization, the 15th century was a liminal time in European history. The Renaissance arrived in Italy by the mid 14th century and did not traverse northward over the Alps until the 16th century. In northern Europe, the 15th century has typically been classified as the tail end of the Middle Ages. However, by the time the 1400s drew to a close in Italy, the Renaissance had been underway there for at least a century. Because incunabula were printed in different European countries including Germany, France, England and Italy, the location in which a book came off the press determined whether it was printed in the late Middle Ages or the Renaissance. Many incunabula were printed in Italy beginning in the 1470s which places them firmly in the Renaissance. For this reason, incunabula have been included in this guide.

The Library's Rare Book and Special Collections Division houses the largest collection of incunabula (around 8,000) in the western hemisphere. While many of the incunabula at the Library of Congress have yet to be cataloged, some incunabula have been digitized and can be found by visiting Digital Collections page of this guide- the Rosenwald and Vollbehr Collections have been made available for online viewing. All original incunabula must be requested in the Rare Books and Special Collections Reading Room. This does not apply to most reproductions of incunabula.