Things this book managed to convince me of:
Florence Maybrick did not kill her husband
The British press - tabloids and broadsheets - always have been and still are moneygrabbing bastards
Things this book failed to convince me of:
James Maybrick was really Jack the Ripper
In the book Harrison seems to have started with the assumption that the diary is not a fake and that Maybrick was really the Ripper and then built a narrative around that without seriously trying to find any proof that would prove or disprove the theory. Of course there are some experts...lots of experts in fact and they have every possible opinion: the ink is from Victorian times, the ink isn't from Victorian times. The handwriting is the same/not the same as on the Dear Boss-letter/Maybrick's signature. The only thing they could agree on was that whoever wrote this diary did know what addiction, and especially arsenic-addiction, did to somebody. That's a good start but considering the other opinions are all over the place not enough.
I missed an instances where she actually took something from the diary and made an effort to check if that could be verified. According to the diary Maybrick killed to more prostitues, one before and one after the Ripper-killings, in Manchester. Harrison brushes over this, claiming it's impossible to find out more about this. Really? When I checked newspaper-archives for a term-paper I found loads from the 19th century. Of course not all of them as detailed as those about the later Ripper-victims but they existed (and despite what crime-shows occasionally make us believe murders don't happen everywhere and all the time, even the murder of 'just' a prostitute would have been mentioned).
She also doesn't try to find an explanation why Maybrick would have switched from Mary Kelly's brutal mutilation to 'just' strangling and then stop alltogether (yes, I'm also just a hobby-profiler who has watched far too much Criminal Minds but one of the universal truths seems to be that serial-killers don't simply stop). He died only in May after the last murder and was not sick all the time from December till his death.
Instead of trying to explain that (or brush away minor inconsistencies in the diary like what the Ripper did with his victims belongings (and body-parts) with more reasoning than 'He didn't remember anymore when he wrote it') she gives detailed accounts of his death, his wife's trial and what happened to her and the family after the trial. As said above: she makes a very convincing case for Florence Maybrick...a far far better than the one against James Maybrick but honestly it is not relevant to the fact if Maybrick was the Ripper or not. The story is sad and tragic and of course a short overview on what happened after his death would have been good but I would have preferred if most of that space had been spent on investigating James Maybrick and not by distracting me with the story of his poor wife in the hope that over pittying her I forget what this book is actually about.