2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/131012Building on the ideas in L E Labuschagne, Composition Operators on Non-commutative $L^p$-spaces, \textit{Expo. Math} \textbf{17}(1999), 429--468, we indicate how the concept of a composition operator may be extended to the context of Haagerup $L^p$-spaces.26 pages. Extension of main results to the non $σ$-finite case, full details of proofs provided, occasional errata correctedOperator AlgebrasFunctional Analysis46L52; 47B33text