Visualizing Variation is a code library of free, open-source, browser-based visualization prototypes that textual scholars can use in digital editions, online exhibitions, born-digital articles, and other projects. All of the visualization prototypes offered here deal with different aspects of the bibliographical phenomenon of textual variation: the tendency of words, lines, passages, images, prefatory material, and other aspects of texts to change from one edition to the next, and even between supposedly identical copies of the same edition. Variants are material reminders of the complex social lives of texts.