This much-needed critical review of the main monitoring techniques conveys profound knowledge of their fundamentals, possibilities and limits, strengths and weaknesses when applied to membrane processes, clearly demonstrating which technique is most suitable for a given process. A practical approach is adopted throughout, providing case studies for the monitoring of selected membrane-based processes. After an introductory section, the book goes on to look at optical and electronic microscopic techniques, followed by electrical, laser and acoustic techniques, and finishes off with process-oriented monitoring techniques.