Jason Fried and David Heinemeier Hansson open Rework with a direct challenge to conventional business wisdom: the elaborate, detailed business plan — long treated as an essential first step — is largely wasted effort in fast-changing markets.

Their core argument:

• Detailed long-term plans are built on assumptions that are almost guaranteed to be wrong by the time they matter, since markets and customer needs shift faster than plans can anticipate
• Time spent perfecting a plan before building anything is time not spent learning from real customer feedback, which is far more valuable
• Planning, in their view, is more useful as an ongoing, adaptive practice than as a one-time upfront document

Their alternative approach: start with the smallest possible version of your idea, get it in front of real customers quickly, and adapt based on what you actually learn — treating the plan as something that emerges through action rather than something completed before action begins.