✨~Deep_Abyss~✨ GRAVE MERCY is a story wrapped all on its own and is told from an entierely different perspective. The next book follows a new character. I liked the first book, but if you want to pursue the series feel welcome. :)
Ben There are five books in the series. Although the first three feature different protagonists, they really do all build on each other and are best read in order, for greatest enjoyment. The final 2 books (Courting Darkness Duology) should definitely be read in order, and after the His Fair Assassin trilogy.
Caitlyn "Books Are My Life" Baker I've actually started with the third book and am going to read this one next, then the first one. I found that it worked out fine and nothing was really spoiled at all.
Sierra The books in this trilogy each follow a different character. However, they each pick up where the other has left off (At least that is how it is with the first two). So, reading these books in order is best.