How can some guys plough through thick textbooks and read them cover to cover?

No.11230695 ViewReplyOriginalReport
I am talking basically sitting every day with no craving towards doing anything else.
Writing down everything and expanding every step, page after page.
Absolute absorption for weeks at a time.
For instance I remember Freeman Dyson saying how he read some old ass Analysis textbooks when he was still in his teens or something.