to maximize your experience and understanding read this on a computer, do some lite research while reading through it. It helps to have multiple windows open with the lyrics and wiki ready. Don't be mentally lazy, you'll only get out of this what you put into it.
Now I'm going to explain each Tool album in detail.
I'm skipping Opiate and Undertow for now because I haven't written those out yet.
Aenima is the transition from proto-history to ancient history. The dates are a rough estimate, I'm not a history expert.
This is the time period when human's started writing, creating symbols, numbers, and developing a sense of past and future.
Much of this album describes how humans developed bigger memory and a longer sense of time.