Quote one assertion from the reading and reflect on what you think the authors were hoping readers would understand from the assertion.

How do the authors define proof?

What 'modern notion' is introduced? $($I am looking for the phrase, not an explanation.$)$

The last part of the Preface is very personal. Speculate as to why it valuable to be aware of this?

Where does the quote in bold above fit in to the study of Geometry, as Henderson and Taimina