suchquestionsforcenturies(unrestrictedbythecapabilitiesofanyhard ware). Theprinciplesgoverningtheinteractionofseveralprocesses,forexample, areabstractansimilartoprinciplesgoverningthecooperationoftwolarge organisation.Adetailedrulebasedeffectivebutrigidbureaucracyisvery muchsimilartoacomplexcomputerprogramhandlingandmanipulating data. Myguessisthattheprinciplesunderlyingoneareverymuchthe sameasthoseunderlyingtheother. Ibelievethedayisnotfarawayinthefuturewhenthecomputerscientist willwakeuponemorningwiththerealisationthatheisactuallyakindof formalphilosopher! TheprojectednumberofvolumesforthisHandbookisabout18.The subjecthasevolvedanditsareashavebecomeinterrelatedtosuchanextent thatitnolongermakessensetodedicatevolumestotopics.However,the volumesdofollowsomenaturalgroupingsofchapters. Iwouldliketothankourauthorsarereadersfortheircontributionsand theircommitmentinmakingthisHandbookasuccess. Thanksalsoto ourpublicationadministratorMrsJ.Spurrforherusualdedicationand excellenceandtoKluwerAcademicPublishersfortheircontinuingsupport fortheHandbook. DovGabbay King'sCollegeLondon x Logic II IT Natural Program Artificialin Logic p- language controlspec telligence gramming processing ification, verification, concurrency Temporal Expressive Expressive Planning. Extension of logic poweroftense power for re Time depen Horn clause operators. currentevents. dent data. with time Temporal Specification Eventcalculus. capability. indices. Sepa of tempo- Persistence Eventcalculus. rationofpast ral control. throughtime Temporallogic fromfuture Decisionprob the Frame programming. Problem.Tem lems. Model checking. poral query language. temporal transactions. Modal logic. generalised Actionlogic Beliefrevision. Negation by Multi-modal quantifiers Inferential failure and logics databases modality Algorithmic Discourse rep New logics. Generaltheory Proceduralap proof resentation. Generic theo of reasoning. proachtologic Direct com- remprovers Non-monotonic putation on systems linguisticinput Non Resolving Loopchecking. Intrinsiclogical Negation by monotonic ambigui- Non-monotonic discipline for failure.Deduc reasoning ties. Machine decisionsabout AI. Evolving tivedatabases translation. loops. Faults and com Document insystems. municating classification. databases Relevance theory Probabilistic logicalanalysis Realtimesys Expert sys Semantics for and fuzzy oflanguage tems tems.Machine logicprograms logic learning Intuitionistic Quantifiers in Constructive Intuitionistic Horn clause logic logic reasoning and logicisabetter logic is really proof theory logical basis intuitionistic.