Carsten Hansen is a FIDE Master as well as a FIDE Trainer from Denmark. Throughout his career, he has authored over 34 books, primarily on openings (English & Sicilian Dragons) and tactics - he also has a tactics course on Chessable!
He is also a columnist for American Chess Magazine & Chess Life and the co-author of Lifetime Repertoires: 1.c4 / 1.Nf3 together with IM Christof Sielecki.