Paolo Romani (IZ1MLL) has recently released version 5.5 of his SDRSharp PDF Guide. The book is available for download on the Airspy downloads page, just scroll down to the title "SDR# Big Book" and choose your language. (At the time of this post only English and Italian are available for 5.5, but multiple languages are available for the older guides).

The latest version brings the book up to 214 pages in length, and adds information about the RTL-SDR Blog antenna kit, and new SDR# plugins like ListenInfo.