"In 1986, Thomas W. Schoener wrote a thought-provoking book chapter describing ecological communities along five organismal and five environmental axes. It was thought-provoking in the sense that Schoener attempted to unify community ecology using a minimal set of variables at a time when ecologists were doubtful of any unifying principle in community ecology. After three decades of Schoener's chapter, community ecologists are still divided about whether there could be a general theory of community. . . . Mark Vellend elegantly attempts to bridge this divide by introducing the theory of high-level processes in ecological communities in his Princeton Population Monograph entitled The Theory of Ecological Communities."---Madhav P. Thakur, Trends in Ecology and Evolution "Vellend (biology, Univ. de Sherbrooke, Canada) provides a useful historical account of the wide variety of methods used in the field to lay the foundation for his proposed resolution of the resulting mess.' The book is well written, profusely referenced, and a worthy addition to the distinguished Monographs in Population Biology series from Princeton University Press." * Choice * "Vellend does a tremendous job, and accomplishes for the field of community ecology what few have attempted, and even fewer, if any, have achieved. . . . With its overall plain language and clear prose, his book is excellent material for pre- and postgraduate students."---Lars Götzenberger and Jan Leps, Conservation Biology "[ Vellend] brings together diverse empirical and theoretical traditions in an unprecedented, engaging, and productive manner."---Max W. Dresow and Jake J. Grossman, Metascience "This is a very useful book for students and researchers."---Kevin S. McCann, Quarterly Review of Biology