This is an indispensable companion if walking the Thames Path, and if you are taking only one book along with you, it should be this one. Others, such as Turner's one on pubs, the National Trail Companion, and the Imray map, are helpful, but you can get along without them if you have this.
Detailed OS maps are included for every step of the way, with the relevant text on the same page. The text itself gives very clear directions, fills you in on local history and landmarks, and points out pubs and other places of refreshment. The balance is just right.
Once the Path reaches London it follows both banks of the river. Here the text usefully splits into colour-coded north and south sections, which run in parallel to each other.
David Sharp, the author, is one of the founders of the Path. His other book, on he London Loop, which he also helped found, is equally excellent.
As another reviewer points out, you can't follow the Path uptream with this book.