Starting in the late 1960's and early 1970's, attempts to improve microbiological analysis got into full swing with the appearance of many products termed, "rapid methods. Remarks like, "You bug-hunters have progressed about three years beyond Pasteur!" have spurred microbiologists to think increasingly about improving the methods for microbiological analysis of body fluids. Scope of Coverage in Monograph is intended to go more deeply into the theoretical and practical aspects of microbiological instrumentation, especially as related to sophisticated, decision-making instrument systems which are designed, developed, and applied specifically to routine microbiological analysis of body fluids. A detailed illustration of the application of these considerations to the actual development of one instrument system will be presented, followed by examples of various instrumented approaches. An evaluation will be made with regard to their adherence to the fundamental microbiological principles which lead to the attainment of the stated goals discussed for instrumented systems.