This book is not about theories. We will explore the world of multiplatform development by examples, making our ideas reality and learning "how to" on the go. The rest of the book will focus on this, but it worth spending a moment to consider the main ideas behind the MVVM pattern and its structure.

The idea behind the MVVM pattern is to separate the data and its logic from the user interface. To do that, we will group the definitions of the entities and the logic to store them in a library we called Model and all the UI related features in another library called View. To manage the communication between those two groups, called application layers, we will develop a third library called ViewModel:

Our components will work together like three teams of people, where the Model groups will have the skills of "what", the ViewModel groups the skills of "when" and the View groups the skills of "how" to present a result to the final user.