In Classical times "incunabulum" signifies "cradle" or "swaddling clothes" and so "beginning". The Latin word was adopted in French (incunables) and Italian (incunnaboli) as well as in other languages. The German Wiegendrucke expresses the same idea.
Incunabula (singular: incunabulum) are books printed during the earliest period of typography--i.e., from the invention of the art of typographic printing in Europe in the 1450s to the end of the 15th century (i.e., January 1501). This limit is convenient but arbitrary, since no special development in the printing art can be connected with it. Such works were completed at a time when books--some of which were still being hand-copied--were sought by an increasingly large number of readers. (Source: Encyclopedia Britannica).
Bernhard von Mallinckrodt (1591-1664), a noted book collector (by the time of his death he possessed a library of nearly five and half thousand works, including some two hundred incunables) is probably best known today for his own book titled De ortu et progressu artis typographicae (On the Rise and Spread of the Art of Typography, published in Cologne in 1640), the first comprehensive study of Incunabula, written to coincide with celebrations to mark what was considered in Germany to have been the 200th anniversary of the invention of printing by Gutenberg. In this work, Mallinckrodt became the first person to use the word "incunabula" to mean the earliest period of printing with moveable type, when he described the era from Gutenberg till the end of the century as "prima typographiae incunabula", the time when typograpjhy was in its swaddling-clothes. And, indeed, it was Mallinckrodt who termed 1500 as the boundary between "antique" typography, and typography of the modern era. (Source: "Essay: Bernhard von Mallinckrodt and the Study of Early Printing," Center for the Study of the Book. University of Oxford: Bodleian Libraries,)
C. van Beughem's Incunabula typographiae, published by J. Wolters in Amsterdam, 1688, is the first catalogue of incunabula that uses the term and includes about 3,000 titles of incunabula.
Some 30,000 editions are known today, in some 450,000 surviving copies, located in about 4,000 different public libraries, mostly in Europe and North America.
“From the 15cBOOKTRADE." A project at the University of Oxford to use material evidence from surviving incunabula to learn more about the distribution and use of printed books and reading practices in the second half of the fifteenth century.
"Incunabula: Dawn of Western Printing" - one of digital exhibitions of Japan's National Diet Library. A useful overview of incunabula: includes a chronological Table on the history of incunabula, a bibliography, a glossary, and links to images.
Material Evidence in Incunabula [MEI] - MEI is a database specifically designed to record and search the material evidence (or copy specific, post-production evidence and provenance information) of 15th-century printed books: ownership, decoration, binding, manuscript annotations, stamps, prices, etc. MEI is linked to the Incunabula Short Title Catalogue (ISTC), provided by the British Library, from which it derives the bibliographical records, and it allows the user to combine searches of bibliographical records (extracted from ISTC) with copy specific records.
The British Library - Incunabula Short Title Catalog (ISTC)- The international database of 15th-century European printing created by the British Library with contributions from institutions worldwide. The database records nearly every item printed from movable type before 1501, but not material printed entirely from woodblocks or engraved plates. 30,518 editions are listed as of August 2016, including some 16th-century items previously assigned incorrectly to the 15th century. Information on each item includes authors, short titles, the language of the text, printer, place and date of printing, and format. Locations for copies have been confirmed by libraries all over the world. Many links are provided to online digital facsimiles, and also to major online catalogues of incunabula such as the Gesamtkatalog der Wiegendrucke, the Bayerische Staatsbibliothek Inkunabelkatalog and Bod-Inc online. For an introduction to searching in the ISTC consult their brief guide.
Library of Latin Classical Editions in the Renaissance - "This is the website for the Research Project on the transmission of classic Latin authors in the incunable and post-incunable periods at the Spanish Distance Learning University (UNED, Madrid). The aim of the research is to study the heritage of incunable and post-incunable editions of Classic Latin texts, paying particularly close attention to the collections conserved in the Iberian Peninsula. The research team's results are published on this website along with two databases: Corpus of Classic Latin Incunabula in Spain (CICLE) and Corpus of Classic Latin Incunabula in Portugal (CICLPor).
INKA - InkunabelKatalog Deutscher Bibliothken. Union catalog that enables searching (in German) for incunabula across German collections .
Reading Early Printed Books - A Guide to the Book as Artifact (By Melinda Hayes). This guide provides you with an introduction to the terminology and aspects of the book as artifact. Finding out about the methods used to create books by hand, and for whom, will help you understand the history behind the texts that are printed on their pages.
British Library - Explore Archives and Manuscripts (Refine Search term to: Incunabula).
Gallica - L'estampe aux XVe et XVIe siècles Access to Incunabula woodcuts and burin prints from Northern Europe.
Library of Congress - Incunabula - The Art & History of Printing in Western Europe, c. 1450-1500.