Thesubtitle,NonclassicalFields,isperhapsnotasaccurateasitmightbeasasummaryofcontent;ortoputitanotherway,ifmyaimfromthestarthadbeentowriteabookonthistopic,partsofthatbookwoulddiffersignificantlyfromwhatfollowshere.Possiblythemostimportantthingmissing,andsomethingthatshouldbesaid,isthattherearetwoquitedistinctpathstoadefinitionofnonclassicalityinquantumoptics.Thefirstisgroundedintheexistence,orotherwise,ofanonsingularandpositrveGlauber-SudarshanPfunction.Thephysicalgroundingisinthetreatmentofopticalmeasurements,specificallythephotoelectriceffect:foragivenopticalfield,canthephotoelectroncountingstatistics,includingallcorrelations,bereproducedbyaPoissonprocessofphotoelectrongenerationdrivenbyaclassicallightintensity,allowedmostgenerallytobestochastic?Viewedatamoreinformallevel,thequestionaskswhetherornottheinfamousproposalofBohr,Kramers,andSlaterfortheinteractionofclassicallightandquantizedatomscanbeupheldinthepresenceoftheobservablephotoelectroncountingstatistics.