This thesis offers a sympathetic interpretation of Marx' s confrontation with Utopia. It begins by suggesting that Marx condemned utopianism as a political process because it undermined the principles of popular self-emancipation and self-determination, principles deemed by Marx to be fundamental to the constitution of any truly working-class movement. As a means of invoking the spirit of revolution, it was therefore silly, stale and reactionary. With regards to Marx's own 'utopia', the thesis argues that the categories which define it were nothing more than theoretical by-products of the models employed by Marx in order to supersede the need for utopianism. As such, Marx was an 'Accidental Utopian'. Two conclusions follow from this. The first is that Marx's entire project was driven by the anti-utopian imperative to invoke the spirit of revolution in a manner consistent with the principles of popular self-emancipation and self-determination. The second is that, in spite of his varied attempts to do so, Marx was unable to capture the spirit of revolution without descending into utopianism himself Such conclusions do not, however, justify the claim that utopianism has a necessary role to play in radical politics. For Marx's original critique of utopianism was accurate and his failure to develop a convincing alternative takes nothing away from this. The accuracy of Marx's original critique is discussed in relation to the arguments put forward by contemporary pro-utopians as well as those developed by William Morris, Ernst Bloch and Herbert Marcuse. In each case, it is argued, political utopianism descends into the messianic elitism ascribed to the utopian process by Marx. Rather than legitimating utopianism, therefore, Marx's failure to develop a convincing alternative means that socialists must develop a more convincing alternative. The conclusion tentatively suggests that the future of socialism lies in its ability to harness, not the spirit of utopia, but the spirit of adventure.