Being a .NET developer, we all are familiar with collections and generics. We know ArrayLists, Arrays, List and Dictionary etc. as collection classes through which we can iterate. This article will explain on how one can create their own custom collection class, which can be iterated through. The article follows step by step process to create a custom collection class to know what actually it takes to create a collection class. The purpose of the article is to learn the concept of collection classes through step by step practical implementations.