They are the same person. Candace is historical romance and C.S. Harris is her Victorian myster pseudonym.  I saw a Sebastian St.Cyr book in the store the other day and came here too look them up.  I discovered the romance part on her website.  Just wondering who she compares too.  If they are any. 

I'm a big Candace Proctor fan - I have them all - but haven't read any of the C.S. Harris books.  I can't think of anyone she compares to exactly.  She has a very distinctive style all her own.  If I were looking for comparisons, I'd say The Bequest and The Last Knight remind me somewhat of some of Marsha Canham's writing; The Bequest being very good, and The Last Knight merely recommended, but not necessarily highly.  Her other novels are simply wonderful.  Some of the best historicals I've read.