This fascicle in the series An Index of Images in English Manuscripts from the Time of Chaucer to Henry VIII reports on the Additional collection, the largest group of medieval (and other) manuscripts in the British Library. The Additional manuscripts, which are catalogued by the British Library together with the Egerton manuscripts, contain many little known manuscripts with imagery as well as a considerable number of books famous for their illustration, i.e. the Bedford Hours and Psalter, the Hours of Elizabeth the Queen, and the Rous Roll. Others such as the Old Hall Manuscript, Mallory’s Le morte Darthur, and the Book of Margery Kemp, are known for their texts. The fascicle describes 322 Additional manuscripts and sixty-three from the Egerton collection. In addition, 431 other Additional and Egerton manuscripts of the period were also examined for images relevant to the project. The textual content of the indexed books include an exceptional number of historical materials as well as numerous literary manuscripts by prominent authors of the period such as John Gower, Chaucer, John Lydgate, and Nicholas Love. This Index listing of representations of all types -- from miniatures to catchwords -- in manuscripts between the dates c. 1380 to c. 1510 is an unparalleled reference work to imagery of the period, which can also be used as a search tool for illuminated manuscripts in the British Library published on-line.