This is one of the four (true) works comprising the Lesser Keys of Solomon (the Notoria is not of the same era.) Less well known than the Ars Goetia, it is nonetheless 1. a distinct work and 2. important to the general tradition it is part of; specifically, it is an astrological work before anything else, which fails to give the sort of detailed list of powers for each of the angels it purports to allow one to summon.
It is broken into two sections. The first details the angels of the hours and the second one the twelve signs of the zodiac. In both cases, seals are constructed and used with a complex table of practice in combination with several invocations. It’s quite a good work overall albeit shorter than the Goetia it shares tradition with.