In this chapter, we dived into the fundamentals of software development in general and explored some of the most widely used design patterns in iOS development. We explored MVC in more detail than others, since it is used in almost all iOS projects and forms the foundation of a majority of applications. In the previous chapters, we used these design patterns multiple times but many a times, we just use things without knowing the underlying concept. This chapter gave you an insight to identify exciting design patterns in the existing code base and to allow you to think in the capacity where you can understand the problem at hand and choose between the design patterns that we discussed in this chapter and beyond. Design patterns is a vast subject in itself, and this chapter provided you with a mere introduction to the concept. We highly encourage you to take some time out, explore design patterns on your own as well, and pick the ones that suit your needs the best. Think of them as tools in your arsenal that you might need anytime to do the job at hand more efficiently.