This book emphasises the important role that protozoa play in many natural ecosystems. To shed new light on their individual adaptive skills, the respective chapters examine the ecology and functional biology of this diverse group of eukaryotic microbes. Protozoa are well-established model organisms that exemplify many general problems in population ecology and community ecology, as well as evolutionary biology. Their particular characteristics, like large population sizes, life cycles and motile sensory behaviour, have a profound impact on their survival, distribution, and interaction with other species. Thus, readers will also be introduced to protozoan habitats in a broad range of environments. 

Genoveva Esteban is a Professor of Microbial Ecology at Bournemouth University (UK). She received her PhD from Universidad Complutense de Madrid (Spain) in 1989 and carried out two post-doctoral positions: one at the National Scientific Research Council in Spain (1990-1991), and the second (1992-1995) at the Institute of Freshwater Ecology (The Ferry House, Windermere, UK).  She then became employed as a senior scientist at the Natural Environment Research Council (NERC, UK) until 2007. That same year, she moved to the university sector to work at Queen Mary University of London (2007-2011).  She has published over 110 original articles and book chapters. Her research expertise is centered on free-living microbial eukaryotes.

Tom Fenchel is Emeritus Professor of Marine Biology at the University of Copenhagen (Denmark).  He received his Ph.D. in 1965 and became employed at the Marine Biological Laboratory as lecturer. From 1970-1987 he became Full Professor at the University of Aarhus and he returned to the University of Copenhagen in 1987 until formal retirement in 2010. He has published about 200 original papers on microbial ecology and population biology and has authored or co-authored five books.