Geometric group theory, group actions on ordered sets, relationship between geometry of 3-manifolds and the algebraic properties of their fundamental groups
Clay, Adam and Rolfsen, Dale (2016). Ordered groups and topology, Volume 176 of Graduate Studies in Mathematics. American Mathematical Society, Providence, RI.
Clay, Adam and Teragaito, Masakazu. Left-orderability and exceptional Dehn surgery on two-bridge knots. In Geometry and topology down under 225–233. Amer. Math. Soc., Providence, RI, 2013.