Mastering the Virgin: Box Set One contains the first 4 books of this series - Friends, Partners, Allies, and Comrades. This series continues the story of Charlotte, James, and Michael and is a spin-off from Buying the Virgin. Be warned that you have to read this series in order, otherwise it will not make sense to you. There are also a number of other sister/spin-off series about these three and eventually their family. If you love hot BDSM then there is a lot of the steamy hot stuff in these books. But there is also more as the relationship between the three develops along with the lives of each character, both within and outside of their relationship.