Tome Dais

Tome Dais is a crafting station for weird books that give you Madness currency when you read them.

Benefits
This is the safest and most manageable way to get Madness for Metaphysics research. You can stockpile the books and keep reading them until you have enough Madness to unlock the next node. Once you do, you'll have only a small amount of Madness left (which won't take long to reduce to 0, thus avoiding any danger). So you can stay at 0 Madness most of the time (unlike when gaining Madness from Atropus planets, etc.).

Drawbacks
These books are costly, and reading them is not instant. Reading 100 books in a row might take a while. When reading too many books, it's more time-efficient to craft more expensive books, as they grant more Madness per use - e.g. Insane Notes are more convenient than Bizarre Fiction.