Abstract By unblocking knowledge bottle-necks and enhancing collaborative and creative input ‘open’ approaches have the potential to revolutionize science, humanities and arts. ‘Open’ has captured the Zeitgeist, but what is it all about? Is it about providing clear and transparent access to knowledge objects: data, theories and knowledge (open access, open data, open methods, open knowledge)? Is it about providing similar access to knowledge acquisition processes (open science)? Obviously it is; however, this is not the whole story. Open approaches require active engagement. This is not just engagement from the ‘usual suspects’ but engagement from a broader societal base. For example, primary data creators need the appropriate incentives to provide access to Open Data – these incentives will vary between different groups: contract archaeologists, curatorial archaeologists and research archaeologists all have different drivers. Equally important is that open approaches raise a number of issues about data a...