A central problem in linguistic semantics is the grammar (lexical semantics, compositional semantics, syntactic behavior) of clause-embedding predicates, such as 'know', 'tell', 'wonder', and 'think'. I present an investigation of this problem through the lens of the interaction with 'about'-phrases. I argue that the best account of this interaction involves the verbs being neo-Davidsonian eventuality predicates that characterize events and states with 'content' (following recent work by Kratzer, Hacquard, and others). Arguments and modifiers of attitude verbs function to characterize the content, leading to a clean separation of syntactic argument structure and event structure; 'about'-phrases in particular indirectly characterize content via a notion of aboutness adapted from work by David Lewis.