The third and fourth volumes of Modern Painters were published in January and April 1856; the fifth, and concluding, volume did not appear till June 1860. The causes which led to this delay are glanced at by Ruskin in his Preface to the fifth volume, and they have been more fully described in the Introductions to Volumes XIII.–XVI. The years which intervened were four of the busiest in Ruskin's busy life, and the tasks which occupied him seemed more important at the moment than the completion of his book. He was hard at work, then, on other things; but also he had much to learn before he could see his way to bring his long argument to a conclusion. The book, which began as an essay in defence of a particular painter, had branched forth in many directions, with something of “the Dryad's waywardness”; and though firmly rooted all the while in strong and definite principles, yet his opinions on particular schools and masters were growing, now in this direction, and now in that, while new subjects of inquiry opened out on every side.

The manifold activities which we have traced in Volumes XIII.–XVI. were pursued in the busy world of men; Ruskin was arranging drawings in the National Gallery, criticising the picture exhibitions, teaching drawing, and lecturing in the great manufacturing towns.