hackeron: Here are two books which are good as starting points. Those are:

- Heading for the Yocto Project: http://bit.ly/2bToiu8
- Embedded Linux Development with Yocto Project: http://bit.ly/2BmfvcD

The first gives you a general idea of what the Yocto Project gives as a benefit when adopted by companies, the second one is a technical book which gives you a good understanding of how it works and how to use it in a deeper way.