The books are in general, very good for describing various techniques and methods of using the different classes of functions provided in DarkBASIC Professional, and if you know what the functions are in DBP, relating them to the DGDK.NET functions are very easy since the names are virtually the same.
Even though the books are geared towards DBP, you may find it in your interests as a source of information in general for all of TGCs product lines, i.e. DarkBASIC Professional, DarkGameSDK (C++ version) & DGDK.NET.
Paul.