Miguel Escobar & Ken Puls 
Master Your Data with Power Query in Excel and Power BI [PDF ebook] 

Power Query is the amazing new data cleansing tool in both Excel and Power BI Desktop. Do you find yourself performing the same data cleansing steps day after day? Power Query will make it faster to clean your data the first time. While Power Query is powerful, the interface is subtle-there are tools hiding in plain sight that are easy to miss. Go beyond the obvious and take Power Query to new levels with this book.