I think Robert McCammon is much better known for his horror books, and horror is not really my thing. But on the MobileRead reading group, which is a pretty good group, someone gave a high recommendation for his lesser known Matthew Corbett historical series, and now here is the second book in that series, The Queen of Bedlam, on sale for $1.99 at Kindle and Kobo US. And, Queen is normally priced at a totally absurd $15.99, which would be a lot even for a brand-new title, and is truly insane for old (2007) booklist. So grab it now if you think you might want it!
McCammon seems to come out with a new book in this series every few years; the seventh and most recent (2019) is Cardinal Black, which has dropped to $2.99 at Kindle US right now. This series gets great comments on the MobileRead forums where I hang out sometimes.
Kindle US: https://www.amazon.com/dp/B099MCC6SN
Mister Slaughter is the third in this series. It has dropped to $1.99 at Kindle and Kobo US, and it’s discountable at Kobo! Be careful, however. It looks as if there may be a new publisher, or at least a new edition, because my 2012 purchase didn’t show up as “already purchased” and the cover is different.
Kindle US: https://www.amazon.com/dp/B099N7XT93
Kobo US: https://www.kobo.com/us/en/ebook/mister-slaughter-2