It seems there are a gazillion testing manifestos out there. This one by Karen Greaves and Sam Laing resonates with me. It covers the essence of what I think is important in straight forward language. If you like this 1-pager, check out their books 
Content of 1-pager:
- Testing throughout OVER testing at the end
- Preventing bugs OVER finding bugs
- Testing understanding OVER checking functionality
- Building the best system OVER breaking the system
- Team responsibility for quality OVER tester responsibility
