Which are my best business books of all time? Well, when you have to get rid of some physical copies, it helps clarify what you really want to keep - and what doesn't make the cut.  I'm busy editing my business book collection prior to moving house.
Some books are ones I'm keeping with me. Some are going into long-term storage. And some, frankly, are off to the charity shop (really terrible ones are reserved for the recycling!)

Here are my lists:
Some of My Best business books of all time
All links are for Amazon UK. Some links may be affiliate links.

Simplify by Richard Koch and Greg Lockwood - an amazing strategy level book
Romancing the Balance Sheet by Anil Lamba
Profit First by Mike Michalowitz

 Financial Intelligence for Entrepreneurs by Joe Knight and Karen Berman

Influence by Robert Cialdini
Keepers but not top priority books
Getting Things Done by Dave Allen - a standard texton productivity but frankly I find it overly complex to actually implement.

Shoe Dog by Phil Knight (Founder of Nike)

Thinking, Fast and Slow by Daniel Kahneman
"All decision making is value clarification"
My old business coach, Dan Bradbury, who's a master NLP  guy,  used to say that all decision making is value clarification. I find that to be a great truth.  Particularly deciding what you're going to get rid of, what you're going to keep on, what you're going to really commit to forces you to think about what you value.

The books you value also tell you interesting things about your focus. It seems the financial analysis books are the ones I'm most focussed on and valuing the most. While overly technical marketing books seem to be getting cut.
Cut, Cut, Cut!
If you're an e commerce business owner and you look at your catalogue honestly, and look at the numbers objectively, you'll probably see that you should probably stop selling quite a lot of the products. I'm sure you've got an emotional attachment to it much greater than any of my attachment to any of my books.

My rucksack for my books is a very small example of a physical constraint. Amazon's Q4 storage limits are a much bigger version of really what is fundamentally the same thing. And your capital constraints are a less physical  (but brutally real!) constraint on what stock you can afford to carry.

So in the end, whether it be mere secondhand books or entire product lines, being forced to cut is a wonderful discipline for any business owner.