It's a book 'on' or 'about'...? It's a question 'on' or 'about'?

[Tedwonny]

On and about seem to be interchangeable at times. How do native speakers distinguish between them? thanks

 

[emsr2d2]

In many cases, they're entirely interchangeable.

 

[Tedwonny]

I was told that 'about' is more general and 'on' is something more profound.

E.g. "about tends to be used for more general subjects; on is frequently used for more specific, detailed works..." From academic vocabulary in use, Cambridge


Is this when we have to distinguish the two?

 

[Tedwonny]

*distinguish between the two