If the world of nonhuman primates offers an emblem of the tensions of modernity, it's Macaca fascicularis, the long-tailed macaque. This alert, adaptable Asian species is one of the world's most familiar monkeys, but also among the most sorely taken for granted. Its behavior is flexible and complex. Its intelligence and opportunism are famous, even notorious. It has been called many names, of which “weed” and “ethnotramp” aren't the worst. Its current population status is poorly known but, by reliable accounts, combines the good news of broad distribution with the bad news of declining numbers. Its relations with Homo sapiens are close, diverse, ambivalent, and in some cases problematic. Although it has recently been reclassifi ed as a species of “least concern” by the IUCN, concern does remain high among some primatologists, who see the long-tailed macaque facing multiple challenges throughout its distributional range. Some of those challenges (of which habitat loss, habitat fragmentation, culling and other population-control actions intended to reduce confl ict with humans, and capture for use in biomedical research are foremost) could lead to local extinctions, disappearance of subspecies, and compromised population viability overall. No wonder, then, that Michael D. Gumert, Agustín Fuentes, Lisa Jones-Engel, and many of their colleagues have felt an urgent need to assess what is known, and to target what isn't known but should be, about Macaca fascicularis. This book is an expression of that heightened concern.