This book constitutes the refereed proceedings of the 9th International Conference on Inductive Logic Programming ILP 99 held in Bled Slovenia in June 1999 The 24 revised papers presented were carefully reviewed and selected from 40 submissions Also included are abstracts of three invited contributions The papers address all current issues in inductive logic programming and inductive learning from foundational and methodological issues to applications e g in natural language processing knowledge discovery and data mining Thisvolumecontains3invitedand24submittedpaperspresentedattheNinth InternationalWorkshoponInductiveLogicProgramming ILP 99 The24acc tedpaperswereselectedbytheprogramcommitteefromthe40paperssubmitted toILP 99 Eachpaperwasreviewedbythreereferees applyinghighreviewing standards ILP 99washeldinBled Slovenia 24 27June1999 Itwascollocatedwith theSixteenthInternationalConferenceonMachineLearning ICML 99 held27 30June1999 On27June ILP 99andICML 99weregivenajointinvitedtalk byJ RossQuinlanandajointpostersessionwhereallthepapersacceptedat ILP 99andICML 99werepresented TheproceedingsofICML 99 editedby IvanBratkoandSa soD zeroski arepublishedbyMorganKaufmann WewishtothankalltheauthorswhosubmittedtheirpaperstoILP 99 the programcommitteemembersandotherreviewersfortheirhelpinselectinga high qualityprogram andtheinvitedspeakers DaphneKoller HeikkiMannila andJ RossQuinlan ThanksareduetoTanjaUrban ci candherteamandMajda Zidanskiandherteamfortheorganizationalsupportprovided Wewishtothank AlfredHofmannandAnnaKramerofSpringer Verlagfortheircooperationin publishing these proceedings Finally we gratefully acknowledge the nancial supportprovidedbythesponsorsofILP 99 April1999 Sa soD zeroski PeterFlach ILP 99ProgramCommittee FrancescoBergadano UniversityofTorino HenrikBostr om UniversityofStockholm IvanBratko UniversityofLjubljana WilliamCohen AT TResearchLabs JamesCussens UniversityofYork LucDeRaedt UniversityofLeuven Sa soD z