I just finished Permission Marketing by Seth Godin. I originally read it because I used the term "Permission Fundraising" in my book Partner Like Paul and I wanted to see if it could refine some of my fundraising ideas.
I think everything in my fundraising book is still accurate. However, this book was so much about marketing that I really couldn't give you any specific take-aways for fundraising. (Maybe I'll write another book and call it Permission Fundraising so I can meld the two ideas together.)
All that being said, I would highly recommend Permission Marketing to anyone seeking to do build any sort of business. It's an older book (Amazon was just a start-up and only sold books), but it shows a path of marketing companies, services and products that is immensely cheaper and more valuable than the interruption marketing most people still default to today. In fact, I can think of a few telemarketers, junk mail senders and spammers I should send this book to!