The concept of the Baroque is notoriously difficult – or, perhaps the same thing, too easy – to define. A long-standing problem in early modern studies is the attempt to elucidate its ‘inherent slipperiness’, a goal, I have discovered, that is as compulsive as it is illusory. After over 150 years of sometimes irascible controversy, and especially after the definitive studies in the late nineteenth century by the German scholar Heinrich Wolfflin, the term is still used haphazardly in popular lexicon: there are Baroque colours, remarks, fashion, even Baroque ice cream; in more scholarly contexts it is used to describe both a style and a period, to delineate both individual subject positions and shared ideologies; it is usually connected with music, art, architecture, although (at least in Anglo-American scholarship) less with literature, and somewhat infrequently with writing specifically in English.

The origin of the term is obscure but much speculated about; it is conventionally related to the Spanish barrueco, an irregular pearl, but it has increasingly acquired a multiplicity of other alleged origins, predominantly derived from the history of art and architecture, frequently pejorative, often suggesting perversity, anachronism, bizarreness, unpredictability, individuality, irrationality, rebellion, theatricality, ornamentation, or oddity, and even simply bad taste, particularly in reaction to classical reason and constraint.