There are parts of this book for all levels of developers. Error handling and logging for new ones, and LINQ and Lamda expressions for others. This is a solid reference book, but I don't think it is absolutely necessary to have in one's library because you can get similar and relevant examples from MSDN. If you find that it takes more time than it should for you to search MSDN for reference information, then you probably should get this book. If you are a non-developer with a basic understanding of programming constructs, this book also may provide some value to you, as topics such as strings, characters,and collections are all covered.