Meant to post here after I'd finished it!
I enjoyed most of it, although the end, where he really starts eulogising Merrett, jarred a bit, for some reason especially the part where he bemoaned the state of his grave (the cemetary it's in is somewhat larger than the impression I felt the author gave of it, too). We have no way of knowing whether or not Minor would have been such a useful contributor if he hadn't murdered Merrett - although of course this particular story wouldn't have the same interest if he had just been an American bibliophile in the UK... there is more human interest in this tale of the creation of the OED than there possibly would have been had he not been committed to Broadmoor. And the tragedy and redemption elements that Simon Winchester played up would have missing too...