This book provides an overview of how settlement processes among nomadic and semi-nomadic populations can result in social and cultural disruption of traditional life. Based on a study among the Negev Bedouin Arab tribes in Israel and the Maasai tribes in Kenya, it focuses, in particular, on the influence of settlement processes on substance use and abuse. The study is the first to provide numbers of users, types of substances, volumes, and frequencies of substance use. Substance use, particularly of alcohol and drugs, represents a new phenomenon in the Bedouin society. New social environments and conflicting sets of values and behavioral norms, which are far from traditional, are persuading factors behind the new trend of substance use. Among the Maasai, the settlement status is a predominating factor in shaping their lifestyle. It greatly influences the availability of substance, the pattern of substance use and their attitude towards it. Although there was no evidence of any hard drug type use among the Maasai, the use of substance is an increasing trend among them. The results may be useful for the formulation of policies and practices related to improving the settlement and living conditions of nomads and semi-nomads, keeping particular attention to the substance use and abuse policies and programs.