Apartfromchaptersongroups(Chapter2),ringsandmodules(Crhapters4,5and6)andfields(Chapters7and11),anumberofconceptsaretreatedthatarelesscentralbutneverthelesshavemanyuses.Chapter1,onsettheory,dealswithcountableandwell-orderedsets,asweUasZorn'slemmaandabriefsectionongraphs.Chapter3introduceslatticesandcategories,bothconceptsthatformanimportantpartofthelanguageofmodernalgebra.Thegeneraltheoryofquadraticformshasmanylinkswithorderedfields,whicharedevelopedinChapter8.Chapters9and10aredevotedtovaluationtheoryandcommutativerings,asubjectthathasgainedinimportancethroughitsuseinalgebraicgeometry.