In this lesson, you learned about several concepts. You built a little application that let you perform a search, as if you were searching Amazon or some other site. You set up a Book class, worked with automatic properties, optional parameters, and named arguments. You built the code required to search a list and displayed the results.
In the next lesson, you are going to learn about the null coalescing operator. This is a nice little operator because it helps us write stabler applications that don't crash.
