The Atlas of Middle-Earth

The level of detail is incredible, but I'm curious about the process behind choosing the most important places in Middle-earth. Did she prioritize certain regions or events?

Reading the books alongside these detailed maps made the world feel so much more real. Has anyone found that their mental image of Middle-earth shifted after seeing this atlas?

Given the complexity of Tolkien's world, I wonder what motivated the author to compile such an exhaustive visual guide—was it a personal passion or a scholarly project?