The Thaumonomicon is an essential tool for all thaumaturges. This book contains a vast amount of knowledge, split into five basic categories: Basic Information, Thaumaturgy, Alchemy, Artifice, and Golemancy. Whenever Research is successfully completed, and the resulting discovery used, the information discovered is added to this book. Finding discoveries can unlock new things to be researched, which will be linked by a line, as well as flashing. Things that require more research will be dark and their text will be in runes. Newly discovered knowledge will be marked by a sparkle. This is the second tool the player should craft as it stores information about obtained research as well as hints towards progression towards more advanced technologies.
Over the course of the game, a player can acquire Warp, and with sufficient warp, a hidden category tab, will be revealed, the Eldritch. Various add-ons for Thaumcraft can also add their own research tabs. A warning: With too many add-ons, the additional tabs can overlap, making some of them inaccessable.
The creation of a Thaumonomicon is similar to that of the later Arcane Constructs: The player must craft a bookshelf and place it down, then right-click it with any wand to transform it into the Thaumonomicon item. No vis is used, or necessary. (BiblioCraft Bookcases do not work for this purpose.)