The following books should be mandatory material for anyone who works with other people:
- Out of the Crisis, and also, The New Economics – W. Edwards Deming.
- Good to Great – Jim Collins.
- Congruent Action – Gerald Weinberg.
Thank you.
Added on 21/07/03 in response to comments: They’re all books that really open your eyes about the nature of working with others, what quality really means, and what it takes to build a truly great company and have fun while doing it.
Darren Hobbs 
WHY???
Read them and find out!
First, you shouldn’t expect people to read based on unmotivated recommendations. There’s a lot of reading out there, and a lot of people punting different works.
If you really want to make a contribution by pushing people toward works you’ve found helpful, explain why the books were helpful to you, and what you got out of them.
Otherwise, how are we to know that they don’t cover subject matter we’re already well versed in?
Also, consider supplying ISBN numbers. I don’t get a hit on Amazon searching for your first recommendation.