We have so many new shiny types in Kotlin: nullable types, read-only types for collections, we have Any and at the same time we have Nothing. What are they all? How do they interact with Java? What caveats should we be aware of when we mix and match Java and Kotlin code? In this talk we completely expose all Kotlin types so that we get a better understanding of what everything is and where it fits in. Svetlana Isakova is a Developer Advocate at JetBrains. She is one of the authors of the "Kotlin in Action" book.