Rights, Priviliges and Obligations Under the Code of Hermes is a work on Hermetic Law by Diurnus of Guernicus, written in 917. Diurnus was a leading scholar of the Hermetic Code in his day, but his writing was often unclear and overly obscure. Nevertheless, this tome, written for the neophyte, is well-regarded as an introductory text and is probably the most widely-known summa on the subject.