Business resource: 22 immutable laws of marketing

We first heard about this book from Seth Godin on the Tim Ferris podcast.  Al Ries and Jack Trout published the edition we have in 1993 - before the internet.
This book and the Laws contained inside have been at the heart of designing, implementing and ending some of our marketing efforts.
Most impactful sections:

• The Law of the Category
  
• The Law of the Opposite
  
• The Law of Perspective 

​Check it out on the interwebs.