Supposedly 95% done (when I was reviewing it), but TBH it's the most unfinished book of all MEAPs I've ever read (& some were ~50%) - plenty of repetitions, intermittent narratives, etc. Sometimes I had a feeling that Cyrille is trying to rephrase exactly the same thought he did few pages before. These feeling were amplified by the length of the chapters - initial ones were long & elaborated, while the final ones are nothing more than 2-4 pagers.
Somewhere there, behind the flawed form, there's a good content. Valuable content that truly makes a lot of sense. But for now, it's quite painful to dig it out, hence no starred review. If you want to read "Living Documentation", wait for the final revision.