This book concentrates on the applications of Petri Nets in manufacturing. Petri Nets are graphical and mathematical tools, and the synchronism of executed actions is the natural phenomenon because of which Petri Nets are considered as mathematical tools for modeling synchronous systems. The primary idea of this theory was modified by several researchers according to their needs, owing to the odd "flexibility" of this theory. The theory is still cultivating and some directions of investigations are also encompassed in this book.