The lean-start up movement has taken pace all over the word for its ability to focus attention on getting to build a functioning business at the expense of least resources. Numerous people have talked about the Lean Start up movement for quite some time - Ash Maurya seems to have given the closest to reality description of what the practical application of the lean means would come up to be.
For all those who have read Eric Ries - Lean Start up; and felt there is still a lot that they felt required explanation of - this book is definitely the go to book. It isn't a very hard read and given that Ash takes through his case study of CloudFire - it is definitely engaging and easy to relate.
A quick read and am sure very easy to relate if you are looking for answers in your entrepreneurial pursuit. - Go get this book and get though the initial working business model.
However, I still find the approach of lean requires you to work on the boundaries of your rationality constantly to keep a track of what new customer segments would work out best for you - even the story of CloudFire towards the end indicates that while the method is well illustrated the pivot to a new opportunity required one to find its existence and then work on the same!
That said, lean start up is still a good approach to start your venture and grow with a systematic learning focus.