This book characterizes the discrete event simulation and analysis using ExtendSim 10. It is a blend between theory and application leaning largely to the weight of the latter. Since the ExtendSim 8 version of the book (13 years ago) there has been significant improvements to ExtendSim, including the new Reliability library incorporated in this new, enhanced edition of the first book. There are two new chapters, one include a model simulating software reliability and inherent availability and the other is a guided project addressing the Launch Availability of a crew launch vehicle (CLV) for a limited launch window. For those unfamiliar with the first edition, there is coverage of just-enough queuing theory for building discrete event models, using the M/M/1 queuing problem involving warmup and steady-state phenomena, as well as methods for analysis and corrective adjustments. Probability distributions and their inverse transfers for random sampling are covered. The StatFit application is used for fitting and analyzing data, including goodness of fit testing. Also, there is an in-depth treatment of random number generators. A bank model is used to demonstrate hierarchical modeling and basic simulation animation. Advanced queuing processes are addressed using a circuit board production example. Detailed modeling is covered using a delivery system transfer depot handing packages for domestic delivery.