I'd just recommend the online docs and some up-to-date articles because there aren't any TFS 2017 books published yet to my knowledge and the TFS 2015 ones would be a quite a bit out of date. TFS is an excellent product and its rate of change has been considerable. If you really want a book then I'd suggest you get one of the TFS 2015 ones from one of the leading publishers. Any one will do. Then be sure to read the release notes for the TFS updates that have occurred since then because they are considerable. I was quite appalled by the many terrible responses you received to your inquiry. Good luck.