To date, very little is known about Dutch ministerial advisers. This can be explained by the combination of their relatively recent arrival (1994) and their uncomfortable fit with the Dutch political-administrative tradition. This chapter aims to lay the groundwork for future analyses of Dutch ministerial advisers by describing and analysing the type of ministerial advisers that have emerged in the Netherlands, both in terms of profile and roles. It is found, firstly, that while earlier ministerial advisers were largely recruited from parliamentary staff functions and civil society, more recently advisers have come from more diverse educational and professional backgrounds, with more or less equal backgrounds in parliament, the civil service, civil society and the party apparatus. Secondly, whereas in earlier governments ministerial advisers mostly held degrees in either law, political science or public administration, the picture has diversified under later governments, including more advisers that graduated in communication studies. Concerning the type of activities ministerial advisers fulfil, relationship management with parliament is the activity on which most time is spent. Over the years the time spent on providing political-strategic advice to the minister and coordination with civil servants has increased in importance, while the importance of giving substantive advice to the minister has fallen. Overall, the role of the ministerial adviser has matured and has grown more accepted and trusted within the political-administrative system. Their presence does not seem to have crowded out the advisory role of the career senior civil service, rather it seems to have contributed to the internalization of a markedly more political-strategic (albeit non-partisan) mindset on the part of senior bureaucrats.