In this monograph two things are undertaken: first, an analysis of the usually accepted version of the enclosure movement in the light of contemporary evidence; and, secondly, the presentation of another account of the nature and causes of the movement, consistent with itself and with the available evidence. The popular account of the enclosure movement turns upon a supposed advance in the price of wool, due to the expansion of the woollen industry in the fifteenth and sixteenth centuries. Landlords at this period (we are told) were increasingly eager for pecuniary gain and, because of the greater profit to be made from grazing, were willing to evict the tenants on their land and convert the arable fields to sheep pasture. About the end of the sixteenth century, it is said, this first enclosure movement came to an end, for there are evidences of the reconversion of pastures formerly laid to grass. An inquiry into the evidence shows that the price of wool fell during the fifteenth century and failed to rise as rapidly as that of wheat during the sixteenth century. Moreover, the conversion of arable land to pasture did not cease when the contrary process set in, but continued throughout the seventeenth century with apparently unabated vigor. These facts make it impossible to accept the current theory of the enclosure movement. There is, on the other hand, abundant evidence that the fertility of much of the common-field land had been exhausted by centuries of cultivation. Some of it was allowed to run to waste; some was laid to grass, enclosed, and used as pasture. Productivity was gradually restored after some years of rest, and it became possible to resume cultivation. The enclosure movement is explained not by a change in the price of wool, but by the gradual loss of productivity of common-field land. This explanation is not made here for the first time. It is advanced in Denton's _England in the Fifteenth Century_[2] and Gardiner, in his _Student's History of England_,[3] accepts it. Prothero[4] and Gonner[5] give it some place in their works. Dr. Simkhovitch, at whose suggestion this inquiry was undertaken, has for some time been of the opinion that deterioration of the soil was the fundamental cause of the displacement of arable farming by grazing.[6] This explanation, however, stands at the present time as an unverified hypothesis, which has been specifically rejected by Gibbins, in his widely used text-book,[7] and by Hasbach,[8] who objects that Denton does not prove his case. In this respect the theory is no more to be criticised than the theory which these authorities accept, for that does not rest upon proof, but upon the prestige gained through frequent repetition. But the matter need not rest here. It is unnecessary to accept any hypothetical account of events which are, after all, comparatively recent, and for which the evidence is available.