"We really did have customers in those early days— true visionary early adopters— and we often talked to them and asked for their feedback. But we emphatically did not do what they said." This startling admission appears in the first page of The Lean Startup: How Constant Innovation Creates Radically Successful Businesses, by Eric Ries (2011). Should we congratulate him on his fresh approach, or laugh at him for missing the only true guidance that product development can trust, that is, the customer? The truth is somewhere between the two. Ries has written a book that some have labelled a key management text of the 21st century, while to a more jaundiced eye it reads like so many business books that come from America, combining evangelical fervour with rather dubious and questionable statements that have not been tested.