The mosaics in the collection of the J. Paul Getty Museum span the second through the sixth centuries AD and reveal the diversity of compositions found throughout the Roman Empire during this period. Elaborate floors of stone and glass tesserae transformed private dwellings and public buildings alike into spectacular settings of vibrant color, figural imagery, and geometric design. Scenes from mythology, nature, daily life, and spectacles in the arena enlivened interior spaces and reflected the cultural ambitions of wealthy patrons. This online catalogue documents all of the mosaics in the Getty Museum’s collection, presenting their artistry in new color photography as well as the contexts of their discovery and excavation across Rome's expanding empire—from its center in Italy to provinces in southern Gaul, North Africa, and ancient Syria. The free online edition of this open-access catalogue, available at www.getty.edu/publications/romanmosaics/, includes zoomable high-resolution photography, embedded glossary terms and additional comparative images, and interactive maps drawn from the Digital Atlas of the Roman Empire. Also available are free PDF, EPUB, and Kindle/MOBI downloads of the book, CSV and JSON downloads of the object data from the catalogue, and JPG and PPT downloads of the main catalogue images.