When it comes to books on dementia there is certainly no shortage of great content that covers the subject from most angles. from: understanding mild cognitive impairment (MCI), living with dementia, dementia health and fitness, the science of dementia and for various carers books.
This is by no means an exhaustive list, it's more a starting point. I recommend downloading a sample of some of these books which most good ebook sites allow. This way up can determine if it's what you're looking for prior to purchasing.
Please let me know if you've read any other great books on dementia. I'll be happy to update the list.