Book excerpt: In recent years, the use of molecular data to build phylogenetic trees and sophisticated computer-aided techniques to analyze them have led to a revolution in the study of cospeciation. Tangled Trees provides an up-to-date review and synthesis of current knowledge about phylogeny, cospeciation, and coevolution. The opening chapters present various methodological and theoretical approaches, ranging from the well-known parsimony approach to "jungles" and Bayesian statistical models. Then a series of empirical chapters discusses detailed studies of cospeciation involving vertebrate hosts and their parasites, including nematodes, viruses, and lice. Tangled Trees will be welcomed by researchers in a wide variety of fields, from parasitology and ecology to systematics and evolutionary biology. Contributors: Sarah Al-Tamimi, Michael A. Charleston, Dale H. Clayton, James W. Demastes, Russell D. Gray, Mark S. Hafner, John P. Huelsenbeck, J.-P. Hugot, Kevin P. Johnson, Peter Kabat, Bret Larget, Joanne Martin, Yannis Michalakis, Roderic D. M. Page, Ricardo L. Palma, Adrian M. Paterson, Susan L. Perkins, Andy Purvis, Bruce Rannala, David L. Reed, Fredrik Ronquist, Theresa A. Spradling, Jason Taylor, Michael Tristem