one major concern of biotechnology is either using enzymes or producing them. enzyme/protein production is therefore an important starting point for biotechnology. bioseparation or downstream processing constitutes about 40-90% of the total production cost. driven by economics, highly selective technologies applicable to large-scale processing have emerged during the last decade. these technologies are slowly diffusing to enzymologists who are working on a smaller scale, looking for fast and efficient purification protocols. the affinity-based techniques (including precipitation, two-phase extractions, expanded bed chromatography, perfusion chromatography and monoliths) described in this volume provide current and new cutting-edge methods. consequently, the book is of main interest to researchers in biochemistry, biochemical engineering and biotechnology, working either in academic or industrial sectors.