Ask HN: Best Introduction to Sales?

I know almost nothing about Sales. I'd like to learn more, since I think it'd be instrumental in better understanding markets.

When I look online for good sales books to read, they all seem based on method / gimmick.

Is there anything more about the general process of sales and/or sales theory? I just want to understand the basics better, not like a 10 step checklist to closing every sale ever.