In this session we are going to consider some lessons that Business Architecture practitioners might learn from Lean. Business Architecture has traditionally delivered ivory tower models which are slow to generate, hard to understand, and require heavy maintenance. We'll start with a '101' level introduction to Business Architecture, discussing both the process of defining a Business Architecture and also some of the models that Business Architecture produces. We'll also try to understand the value of Business Architecture. We'll then start to map some Lean Principles to Business Architecture and try and understand how we could potentially optimise the value stream. We'll consider where Business Architecture can be wasteful, discussing the diminishing value of information and the concept of analysis paralysis. Finally I'll introduce you to a leaner approach to Business Architecture that focusses on rapid techniques for model generation and heavier engagement of system actors in both the development and the maintenance of models. I'll also share my technique for rapid enterprise modelling which can help you to build a capability model in hours rather than weeks/months.