This volume continues the series of Ruskin's Oxford Lectures from Volume XX., and covers the years 1871 and 1872, to which, however, Fors Clavigera will, in a later volume, take us back. The works here included are: I. Three Lectures on Landscape, delivered in January and February 1871. II. The Relation between Michael Angelo and Tintoret, and III. The Eagle's Nest; both of which were delivered in the earlier terms of 1872. IV. Ariadne Florentina, delivered in November and December of the same year. In the Appendix are given, as explained below (p. xli.), Notes for two later courses—“Studies in the Discourses of Sir Joshua Reynolds” (1875), and “ Readings in Modern Painters” (1877). This arrangement, which is convenient for the better distribution of the material into volumes approximately of the same length, has the further advantage that the topics mainly treated in these later courses are closely connected with the doctrines enforced in The Eagle's Nest