I've heard great things about Predictable Revenue (https://www.amazon.com/dp/B005ERYEGU) and The Sales Acceleration Formula (https://www.amazon.com/Sales-Acceleration-Formula-Technology...) but haven't read either yet. I think they're focused more on selling products than services, but not 100% sure.

"Sales" is very broad.

My favorite book about the act of selling (i.e. pitching) is "Pitch Anything" - http://www.amazon.com/Pitch-Anything-Innovative-Presenting-P...

If you're looking for an overall sales primer/bible, your best bet is probably The Sales Acceleration Formula http://www.amazon.com/Sales-Acceleration-Formula-Technology-...