Lean Management, the [ liin mänäschmänt ] – to manage projects or companies or tasks in a very effective way, without (administrative) overhead. To catch the slim line. Downsize projects and processes to their really needed size. Strip off useless ballast.
In software projects often associated with the scrum or canban methods. Process oriented approach not pure end result focussed. Not to write 500 pages of requirements before starting the project. Better start with a clear defined project goal and some sketches/ user stories. Then start over and check every 14 days, if the projects develops in the right direction, if not adjust new.
Some thoughts about agile methods and lean (startup) are written by Stefan Lange in his blog called agilosoph
Lean management/ – production/ – development include the Kaizen approach – a continuous process of improvement – which, at the end wants to increase the level of quality with parallel savings of resources.
… about Kaizen: http://kaizenfieldbook.com/
… about Lean XYZ you can find a top ten book list here: http://thekaizone.com/2014/05/the-top-10-lean-books-of-all-time/