2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/166090This purpose of this book is twofold: to provide a general introduction to higher category theory (using the formalism of "quasicategories" or "weak Kan complexes"), and to apply this theory to the study of higher versions of Grothendieck topoi. A few applications to classical topology are included.735 pages. An updated and expanded version of the earlier submission math.CT/0306109 2/10/07: Various minor additions and corrections; added some material on combinatorial model categories to the appendix. 3/8/7: Actually uploaded the update this time; added material on fiber products of higher topoi. 7/31/08: Several sections added, others rewrittenCategory TheoryAlgebraic Topology55U40 (Primary), 18B25 (Secondary, 18G30 (Secondary)text