OKRs, From Mission to Metrics: How Objectives and Key Results can help your organization achieve great things.

One if the best, most insightful books for understanding and implementing OKRs as a tool. Read! Then read again.The author has done A LOT of research and work to bring together what has been written about OKRs, as well as MBO and Hoshin Kanri, into a useful easy read that is immediately applicable.

If you want to know OKR, performance measurement system used in Google and don't have much time to read. This is the book for you.

Expected more. Also, tools that were promised later was a reference to sign up with them. However, a good introduction to OKR's

This is perhaps the best book I’ve ever read about OKRs. Clear, concise and the point. Mello manages to explain the how that is missing in most of the literature. Highly recommended.

Great if you want to get a quick puck fast off what OKRs are. The book shows best practices with real practical examples.

Great , easy to use and with all the basics to get startedYou have to start with this one

Ummm, so that's the Shuttle Columbia's last mission crew on the cover of this book. Kinda awkward. :-/

The book started great: a lot of references to interesting books, researches, and analysis. But starting the chapter about vision and mission it becomes very promotional about the company were author works. And when later when the author attacks Google saying that they not only doing OKRs wrong but also don't need them because they are getting so much money from AdWords and can just relax and do nothing I just stopped reading.