I now understand dendochronology.
I remember learning about this and thinking it is so cool - at some museum years ago. Seeing the circles in a slice from an old tree with notes on it saying things like
"The Battle of Hastings took place in the year this circle was formed" or -
"The Magna Carta was signed here" and stuff like that. There was also one that showed the "overlap" so a particularly good or bad year was matched with an older tree that had the same good or bad year and so one could take it back further and further.
I'm still reading the book - and although there is much I already knew, I am really enjoying it and it is certainly making the whole thing clearer in my mind.
Just clarifying things like the common mistake; 'we evolved from monkeys'. I was aware we did not evolve from modern monkeys - but such a saying is of course inaccurate - humans and monkey's evolved from a common ancestor.