Mixed-acid fermentation is the core step of the MixAlco process, which converts biomass in hydrocarbon fuels. In this work, Smith is the first to sucessfully operate a large-scale ( 3000 gallon) pilot fermentation at steady-state. From this experiences, he details challenges of operation and the tools and techniques he developed that eventually lead to sucessful operation. Based on the pilot fermentation work, Smith designed two experiments to investigate the behavior and optimal concentration of nitrogen in mixed-acid fermentation. A theme throughout this work is the challange of previous methods and assumptions. In each chapter, Smith builds on previous work, provides new insight, and advances the art of mixed-acid fermentation. In addtion to his research findings, Smith developed new experimental and analytical techniques, refined old definitions, and added new ones. This is a must read for any student, scholar, or engineer of mixed-acid fermentation.