It's not that I haven't been working. I've been working on transcribing and now translating an early fifteenth-century history of invention. But neither transcription nor translation is the same style of writing as academic prose. A book review may be a rather specialized subset of the genre, but it is of it nevertheless. As I edited the review into coherence, adding and amending, I realized that I've spent long enough doing other kinds of work to finally be refreshed from the endlessness of finishing off my dissertation. I took a long vacation from academic writing - doing other, relevant things the while - and now I'm ready to start afresh.
I might even be ready to read my dissertation again.