Scholars differ on the key question of whether the actual emblems in question are the visual images, the accompanying texts, or the combination of the two. This is understandable, given that the first emblem book, the Emblemata of Andrea Alciato, was first issued in an unauthorized edition in which the woodcuts were chosen by the printer without any input from the author, who had circulated the texts in unillustrated manuscript form. Some early emblem books were unillustrated, particularly those issued by the French printer Denis de Harsy. With time, however, the reading public came to expect emblem books to contain picture-text combinations. Each combination consisted of a woodcut or engraving accompanied by one or more short texts, intended to inspire their readers to reflect on a general moral lesson derived from the reading of both picture and text together. The picture was subject to numerous interpretations: only by reading the text could a reader be certain which meaning was intended by the author. Thus the books are closely related to the personal symbolic picture-text combinations called personal devices, known in Italy as imprese and in France as devises.
Emblem books, both secular and religious, attained enormous popularity throughout continental Europe, though in Britain they did not capture the imagination of readers to quite the same extent. The books were especially numerous in the Netherlands, Belgium, Germany, and France. Andrea Alciato wrote the epigrams contained in the first and most widely disseminated emblem book, the Emblemata, published by Heinrich Steyner in 1531 in Augsburg. Another influential illustrated book was Cesare Ripa's Iconologia, first published in 1593, though it is not properly speaking an emblem book but a collection of erudite allegories. Two English emblem books were published in 1635, the famous Emblems of Francis Quarles, and George Wither's A collection of Emblemes, Ancient and Moderne. Many emblematic works borrowed plates or texts (or both) from earlier exemplars, as was the case with Geoffrey Whitney's Choice of Emblemes, a compilation which chiefly used the resources of the Plantin Press in Leyden.
- the OpenEmblem Project - housed at the University of Illinois at Urbana-Champaign
- Alciato's Book of Emblems
- The English Emblem Book Project
- Glasgow University Emblem Website including French and Italian emblem books
- Alciato at Glasgow - 22 editions of Alciato from 1531 to 1621
- Emblem Project Utrecht - "27 Dutch love emblem books, religious as well as profane"
- Mnemosyne Emblem Project - a dozen digitized emblem books
- Literatura Emblemática Hispánica
- Arthur Henkel & Albrecht Schöne, Emblemata, Handbuch zur Sinnbildkunst des XVI. und XVII. Jahrhunderts, Verlag J.B. Metzler, Stuttgart - Weimar 1996, ISBN 3-476-01502-5. Massive catalog reproducing emblems with texts from all known 16th and 17th century emblem books.