This is extremely dense book. It wins extra points for being concise. You can read it in hour or two. There is also audiobook read by the author.
I still can't make my mind about Derek. It's either he is genius and hiding it very well. Or he is the most naive and luckiest man. Either way read the book, it's worth it.
One thing really surprised me. Derek talks about completely different attitude of running a business. Every single business I know is there for one reason — money. You might think that's the best way to run the business. Sure, but it's definitely a survivorship bias. Money focused business might live longer but it's like a walking dead — it ruins the scenery.
It's rare to find customer focused business. Everybody says they focus on their customers. Yeah right, as long as their business is growing. Are your customers really interested in your business growth? I don't think so. They are interested in a great service/product. In fact larger companies tend to have worse service than their small competitors.
The author's mindset is similar to Basecamp. Focus on customers. You are not going to need it. Adjust as you go. No funding.
I like his "HELL YEAH! or no" principle. I saw it many years ago and it got stuck with me for all that time.
Delegate or die: Answer the question and explain the thought process and philosophy behind the answer.
Trust, but verify: Remember it when delegating. You have to do both.
A real person, a lot like you: Technology depersonalises humans, but there are people on the other end, remember that.
Quote from Steve Blank: No plan survives first contact with customers.
You should feel pain. If you do you will always know what to improve.
If you like the book I would recommend to follow Derek's blog.