Author: Ronald Brown Title: Crossed complexes and higher homotopy groupoids as non commutative tools for higher dimensional local-to-global problems Abstract: We outline the main features of the definitions and applications of crossed complexes and cubical $\omega$-groupoids with connections. These give forms of higher homotopy groupoids, and new views of basic algebraic topology and the cohomology of groups, with the ability to obtain some non commutative results and compute some homotopy types in non simply connected situations. Author's address: School of Computer Science, Bangor University, Dean St., Bangor Gwynedd Ll57 1UT, UK Web page: www.bangor.ac.uk/r.brown Futher information: This is a revised version (2008) of a paper published in Fields Institute Communications 43 (2004) 101-130, which was an extended account of a lecture given at the meeting on `Categorical Structures for Descent, Galois Theory, Hopf algebras and semiabelian categories', Fields Institute, September 23-28, 2002. The author is grateful for support from the Fields Institute and a Leverhulme Emeritus Research Fellowship, 2002-2004, and to M. Hazewinkel for helpful comments on a draft. This paper is to appear in Michiel Hazewinkel (ed.), Handbook of Algebra, volume 6, Elsevier, 2008/2009. MATHEMATICS SUBJECT CLASSIFICATION: 01-01,16E05,18D05,18D35,55P15,55Q05 arXiv: math/0212274