Listed here are the top books that I have found helpful in the applying the power of new business intelligence (BI) technology to business problems.

M is for (Data) Monkey
If you want to get behind the scenes of PowerQuery, this book will open up the world of a powerful new language, M.

It is written well and  guides the user to an understanding of it's uses and power

Learn to Write DAX

If you want to calculate formulas for use in PowerBI or PowerPivot, you will need to learn DAX (Data Analysis Expressions). This is a beginning book that will walk you thru the basic fomulas and syntax 

BI Best Sellers

Power Pivot and Power BI the Excel user's guide to the data revolution
Rob Collie is one of the founding engineers behind Power Pivot so his book gives great insight into some of the early lessons. Now in it's 2nd edition, it is a MUST READ for anyone who is learning how to use these 2 products.