The book investigates the Yellow Leaf People or Mlabri ethnic group at Huay Hom Village, Rong Kwang District, Phrae Province. The group resides in deep jungles in the mountains of northern and northeastern Thailand. Evidence indicates that the ethnic group was found in Phu Khiaw region of Chaiyaphum Province in 1919, in Phu Kradung of Loei Province, Wiang Sa Mountain in Chiang Mai, Doi Chang Mountain in Chiang Rai, Rong Kwang and Song Districts of Phrae, and Sa and Na Noi Districts of Nan. The ethnic group does not hold permanent residence. They move through thick jungle in cycle within a 30-kilometer radius. They build simple residences with the roof made of tree branches and banana leaves. About 3 to 4 families stay close together so that they can help one another. Nowadays, the number of Mlabri is dwindling due to the reduction of forests, scarcity of food, sicknesses, and premature death. They hunt and collect wild vegetables for food. Some families become workers for local villagers or Hmong hilltribe and they get pigs or money in return. A family has about 4-5 members. The marriage ceremony is simple. A man just asks the woman’s parents permission to live together as husband and wife without dowry. Divorce also does not require any fine. Sexual relationships are common. Men and women can marry many times as long as monogamy is observed. Health care is minimal. Child delivery takes place with the help of women only. No man is allowed into the area. Herbal medicine is the only source of treatment. Social changes have altered the lifestyle of Mlabri. The group has to adjust itself to new culture in order to survive. Furthermore, food sources and forests have been drastically reduced.