BOOK REVIEW 69 world Neolothic revolution was slow, probably because it had to spread vertically through different latitudes with different climatic conditions and it may also be that population pressure in the Old world was less. Consequently quality of Neolothic revolution was also low. While the old world produced highly productive staple crops like Wheat in the intial stages, it took very long time to convert maize in to rich source of food in New world. When Europeans encountered Australian aborigines in 15th and 16th Centuries they were still preoccupied with paleolothic ways. In America the metal was being used for idols and not for weapons. The first centre of civilization, Sumeria inherited this Oldworld Neolothic revolution which utilized the potential of animals and food grains. The important feature that distinguishes Oldworld during this period is the quality of livestock. Horse was present in Oldworld but not in the new world. Further the domesticated livestock made soil fertile and they proved worthy companions in times of scarcity. Even the plants became tolerant of grazing cattle, getting adapted to them, Crosby calls these plants as Weeds. The ability to digest milk in this part of world might have also helped people to tide over starvation. Fewer people in Americas and Australia can tolerate milk. Concommitant with intensive agriculture and domestication of animals, the environment also grew congenial to the growth of pathogens which produced diseases like Small pox, Measles, Typhoid etc., which are crowd diseases. By about 3,000 years ago human being in the Oldworld became immune to these diseases, but he was a source of destruction when he travelled to the virgin areas of New world. Siberia which had many elements of Neolothic revolution but differed from Old world in that agricultural production was less and was thinly populated had to bear the brunt of Western influx in 16th and 17th centuries with their deadly diseases and by 20th century Siberian population consisted of 85 per cent Russians and the rest were indigenous. This experience held serious portents to the future of New world largely bereft of Neolithic revolution. Three examples in middle ages set out the factors which would prove crucial for the European migration. In the North Atlantic Iceland, Europeans settled by 870 AD and this was Europe's first overseas colony and later Europeans spread to Greenland and Vinland. Inspite of having certain advantages over Skraelings (Natives of these lands) like possession of animals including the much needed bull and the ability to digest milk, these colonies were not sustained for long. Skraelings enjoyed numerical superiority as the region with its hostile climate did not attract large European expeditions and even intense agriculture was not possible here. These lands were too remote from Europe to receive pathogens and less populated to maintain crowd diseases. These diseases were epidemic rather than endemic proving disastrous to the people settled there. Small pox and Black