The way in which this chapter attempts to bring ‘Marx in the Field’ is through the exploration of how some key questions, central to all empirical research, can be addressed in ways informed by Marxian categories, methods and approaches. These key questions are what do we want to know? Why? How can we find out? In engaging with these questions, the chapter will address the tasks of ‘problematisation’ and the purpose of empirical investigation, that is, to generate new knowledge (versus ‘verification’). In this process there are necessary protocols of what constitutes empirical evidence and assessing the quality/validity of evidence. Research inspired by Marx's ideas has to be disciplined by such protocols. The chapter will also explore the particular challenges posed by Marx's notion of what is ‘visible’ (observable, hence empirically researchable) and what is necessarily ‘invisible’ in capitalism (e.g. surplus value – or value more generally) – issues of essence and appearance. Notably, ‘appearance’ is no less ‘real’ than essence, and they are fundamentally connected as in Marx's conception of commodity fetishism; still their distinction should be acknowledged in empirical investigations. Finally, the chapter will conclude with observations on researching class, which is to say the ensembles of objective and subjective conditions encapsulated (and differentiated) as class (1) relations, (2) dynamics, (3) experiences, (4) beliefs and (5) practices. This follows Balibar's thesis that in a capitalist world, class relations are ‘one determining structure, covering all social practices, without being the only one’.