I don't have permission to create the page (or talk page) for Grimoire Anthology 3, so here's a quick list of its contents:
The book is divided into four parts, between them containing a total of 10 chapters composed of lore tabs, grimoire entries, mission dialogue, and new content.
Part I, "Encrypted", covers the Exos and Rasputin, and also includes several entries from the journal previously only available with The Taken King's collector's edition. Part II, "The Architects", includes entries from eight of the fifteen Ares One armor ornaments, and a number of entries regarding Clovis Bray and its projects. These include ghost fragments for Meridian Bay and Clovis Bray itself, three new entries, Ghost Fragment: The Golden Age, Concierge AI dialogue, Dr. Shirazi's notes from the Transmission ARG, the SIVA grimoire card and item descriptions for the Nanomania, Red Miasma and Cosmoclast suits, and the Nascent Dawn lore entries. Part III, "The Excavators", covers the Ishtar Collective with A Stranger's Call, Tractor Cannon, and several Vex and Vault of Glass ghost fragments, then covers the Exo Stranger's grimoire entries. Finally, Part IV, "Retrieval", contains the lore book "The Man They Call Cayde".