This chapter introduces probability theory and analysis techniques for performing classical queuing system analysis. Mean Value Analysis is perfectly acceptable for simple systems involving few customers and queuing systems. The chapter discusses the application of the techniques that enable one to calculate, under certain assumptions and conditions. It discusses an iterative method for finding some of the performance measures of interest without calculating the aforementioned distributions. The general algorithm allows us to compute average values for queue length, throughput, server utilization and wait time by starting with an expression for one customer in the system and working up to any number of customers. The algorithm is iterated until we reach the desired network population, where we can calculate the mean performance measures for the network. Operational analysis is based upon the observation of basic, measurable quantities that can then be combined into operational relationships. The observation period for which the system is analyzed is finite.