Game Theory is a branch of mathematics with an enormous amount of real life applications. Cooperative Game Theory is the branch of Game Theory which assumes that groups of players are the primary units of decision-making, and may enforce cooperative behaviour. This branch is studied in this bachelor degree thesis. On the one hand, the theory behind Cooperative Games is presented, as well as some relevant concepts such as the Shapley Value, the Shapley-Shubik Power Index or the Decisiveness Index. On the other hand, some of its applications (in fields that vary from Cryptography to Graph Theory) are replicated and analyzed.