The document presents an overview and summary of the increasing variety of methods in use for detecting and monitoring microorganisms in the environment. A general overview of detection methods is provided for readers with a general interest in the topic of microbial detection methods which surveys the variety of techniques used in the study of microorganisms in the environment. A more specific analysis of techniques section provides a more detailed examination of individual detection methods. The techniques discussed include those based on direct detection, on culturing, and on nucleic acid hybridization. It is intended to be used as a reference document for regulatory officials, scientists, and others interested in microbial biotechnology.