The one is more imperative the other more loose.

Both are No BS.

I read The Monk and The Riddle and then Rework shortly after eachother.

The Monk etc is a great book about how startups really work. From the mouth of a top advisor of VCs in Silicon Valley. That sounds strong and confident and so is the book.
Illustrated with great real life example and stories around that – funeral.com, the Amazon of funeral goods, for heaven’s sake…
Talks about the business side, but also discusses the need for a vision the founders need on what they want the startup to achieve.

What are investors really look for. For them your business plan is one in very many.

Is there a big market? Can the product win and defend a large share? (Peter Thiel – look for a monopoly in Zero to One). Can the team do the job?

They are looking for passion. Money should not be the driver. Passion should.

Make plans, but don’t assume you can stick to them for very long. Be flexible. Also the investors should recognize this.

“In a Brave New World startup, there’s no existing market, no incumbent competitors, and no economic model, you’re literally investing the business as you go along.”

I take that opportunity to link to Fried and Heineman say in Rework – a plan is ok but it is all guesswork, they say, so do not worry too much if it needs changing; actually expect it to change (or you would be psychic).

Jason Fried and David Heineman Hansson are furthermore a lot less stern but and take a more relaxed standpoint. But they are from the other side of the table.

Their book has a number of nice bangs:
Learning from mistakes is overrated. I like that one against the “fail fast” silicon valley hype.
Do it for yourself – ignore the world (Ignore Everybody from Hugh Macleod).
Do not listen to your customer they do not know either (read Clayton Christensen’s The Innovator’s Dilemma“).
Working too hard is stupid.
Small is fine – big not an objective.
Entrepreneur, a word that it sounds like a members-only club.

I like that.

Very practical no-nonsense advice.
In short: don’t bullshit around, do the work (Do The Work – Steven Pressfield).

Both very informative, funny. Read like a novel.