Case studies of net losses of tropical forest cover (n= 152) were analyzed to determine whether the proximate causes and underlying driving forces of tropical deforestation fall into any patterns. Study areas range from a community to a multiprovince area, and cases span time periods from 1880 to 1996, with 1940 to 1990 being the most frequently covered period. The 152 cases of tropical deforestation were taken from 95 articles published in 40 journals covered by the citation index of the Institute for Scientific Information (Geist and Lambin 2001). The criteria for selecting studies were the following: quantification of the rates of forest-cover change; net loss of forest cover during at least part of the study period; investigation method based on quantitative data or in-depth field investigations; consideration of clearly named factors as potential causes of deforestation, including basic features of the socioeconomic setting and the natural resource endowment; and absence of obvious disciplinary bias. We assumed that each study revealed the actual causes of deforestation in the study area. Therefore, our comparative analysis of case studies evaluates which causal patterns leading to deforestation are most often found in different tropical regions. Four broad clusters of proximate causes were identified: agricultural expansion, wood extraction, infrastructure extension, and other factors. Each land use category was further subdivided; for example, agricultural expansion was divided into permanent cultivation, shifting cultivation, cattle ranching, and colonization (Figure 1). Underlying driving forces were categorized into five broad clusters: demographic, economic, technological, policy and institutional, and cultural factors. Each was further subdivided into specific factors; for example, cultural or sociopolitical factors were partitioned into public attitudes, values and beliefs, and individual or household behavior (Figure 1; Ledec 1985, Lambin 1994, Ojima et al. 1994, Turner et al. 1995, Lambin 1997, Contreras-Hermosilla 2000). Causal factors were quantified by determining the most frequent proximate and underlying factors in each case. The major interactions and feedback processes between these factors were also identified to reveal the systems dynamics that commonly lead to deforestation. Three modes of causation were distinguished: single-factor causation (ie, one individual underlying factor driving one or more proximate factors), chain-logical causation (ie, several interlinked factors in combination leading to deforestation), and concomitant occurrence (ie, independent, separate operation of factors causing deforestation). Results were broken down by broad geographical regions (Asia, n= 55; Africa, n= 19; Latin America, n= 78). They are given in order of decreasing importance, with factors occurring in less than 25% of the cases not reported.