My PhD thesis concerns trade union responses to austerity in Belgium, Greece and Ireland (2008-2016). It explores the power resources trade unions in Europe have drawn on during these crisis years, and seeks to establish if unions are cultivating new sources of power and influence, as traditional sources wane. My research points to unions being under sustained pressure, but it also presents evidence of effective union revitalisation, including through the formation of new coalitions with civil society actors, through the use of innovative legal approaches to problem-solving, and with unions reaching out to new, often atypically-employed, groups of workers. Notably however, the national level remains the primary concern for unions, and the European Union (EU) level of action remains adjunct to what unions do.