The book "blockchain for dummies" provided by IBM contains 6 chapters on 41 pages. (Download from IBM)
The chapters 1 & 2 describe the basic of blockchain technology.
From my point of view, this part is a bit too shallow, because there is no single formular inside this book ;-)
But there are some nice illustrations given:
and the differences between a public blockchain and corporate blockchains are good explained including their consequences.
Chapter 3 is about where companies can use blockchains. This chapter i did not understand. It is all about frictions which companies have to overcome. But these frictions are not special to blockchain (like "innovation restrictions").
In chapter 4 some examples are shown. These examples are very universal examples, which are too abstract in my eyes.
Chapter 5 contains information about a project of the Linux Foundation: Hyperledger.
This is very nice opening for https://www.hyperledger.org/.
Chapter 6 comes up with ten steps to your first blockchain application.
My conclusion: a very nice book and really ok for free. But I wouldn't spend any money on it...