The objective of this article is to introduce two ethnic groups, the Hmong and theYao, in the North of Thailand who have maintained their original way of life. Although these groups have remained behind in terms of technology such as the means of production, education and public health, these ethnic groups are peaceful and hard working. The author is very interested in their culture, livelihood, traditions, rituals, beliefs and many social aspects, however he does not give many details of population, geography or their historical background. In the last part, the author proposes that there are 2 aspects about these ethnic groups to be considered; 1. they cultivate with shifting cultivation, baring the forests, burning the forests and shifting their land which cause the destruction of the ecological system. and 2. opium cultivation. However, the author’s standpoint is to try to explain the value of preserving these original communities without changing or destroy their ways of life. The only aspects in which the author agrees with the Thai Government is supporting their agriculture by long planned assigning of agricultural experts to suggest and promote replanting instead of opium cultivation. (page 16-18)