This essay is an evocation of Arthur Symons’s intellectual and aesthetic engagement with darkness. In the 1890s, Symons was the leading English language critic of two of the most important French movements of the fin de siècle: decadence and Symbolism. In ‘The Decadent Movement in Literature’ (1893), Symons established the various literary and artistic dimensions of decadent art, providing an English-speaking audience with an impression of a movement which has always been characterised by its engagement with darkness, whether literal, psychological, or spiritual. By the time he published The Symbolist Movement in Literature (1899), Symons had distanced himself from decadence, but he retained an interest in shadows, darknesses, and the unknown. Symons was also a well-known poet, and from his earliest poetry onwards displays a constant fascination with images of the dark. Darkness was, for Symons, more than an atmospheric means to evoke the sense of a century coming to an end, however; rather, it was a space of uncertainty and indeterminacy, in which he was able to symbolise his spiritual concerns. I argue that the darkness was, for Symons, always spiritualised, a searching after the divine, even if unsuccessfully.