37signals are most well known as the creators of Basecamp. I love their approach to business and highly recommend you buy their book Rework. It’s packed full of really useful business advice that’s incredibly down to earth and makes much more practical sense than any other business book I’ve read.
They’re now giving away free copies of their book, Getting Real: The smarter, faster, easier way to build a successful web application.
On Amazon this book currently retails at £15.89 for the paperback and £6.99 for the Kindle version, so I recommend you download your copy whilst it’s free!