There are three novels, and I am reading the second one now, Witch Finder. They are great fun, and if you like Solomon Kane, they are worth checking out. They are like reading a Hammer horror movie from their heyday.
As they often do, the Black Library are reissuing all three novels in an omnibus edition; due in November. The edition will include two previous short stories and a brand new tale. I guess that's kind of like a band releasing a greatest hits album with a single new track to entice fans to buy a collection they already own.
But, it is a sweet cover...