▁functional ist ▁logic , ▁and ▁indeed , ▁Davis ▁came ▁to ▁be ▁a ▁leading ▁figure ▁in ▁this ▁school ▁of ▁soci ology . ▁ ▁As ▁a ▁dem ograph er , ▁Davis ▁was ▁intern ation ally ▁recognized ▁for ▁his ▁expert ise ▁in ▁world ▁population ▁growth ▁and ▁resources , ▁the ▁history ▁and ▁theory ▁of ▁international ▁migration , ▁world ▁urban ization , ▁dem ographic ▁transition ▁and ▁population ▁policy . ▁ ▁Pub lished ▁works ▁Kings ley ▁Davis ▁was ▁a ▁pro l ific ▁scholar ▁who ▁published ▁numerous ▁research ▁articles , ▁book ▁chap ters ▁and ▁books . ▁ ▁Books ▁ ▁Chap ters ▁ ▁Ed ited ▁volumes ▁ ▁Other ▁writing ▁In ▁the ▁popular ▁press , ▁Davis ' ▁work ▁appeared ▁in ▁" S cient ific ▁American ," ▁" S cience ," ▁the ▁" New ▁York ▁Times ▁Magazine ," ▁" Comment ary ," ▁" Foreign ▁Affairs " ▁and ▁numerous ▁newsp apers . ▁ ▁In ▁ 1 9 5 7 , ▁Davis ▁predicted ▁that ▁population ▁of ▁the ▁world ▁would ▁reach ▁six ▁billion ▁by ▁the ▁year ▁ 2 0 0 0 . ▁He ▁was ▁remark ably ▁close ; ▁that ▁population ▁figure ▁was ▁reached ▁in ▁October ▁ 1 9 9 9 . ▁ ▁References ▁ ▁Further ▁reading ▁David ▁He er ▁and ▁Kings ley ▁Davis . ▁" K ings ley ▁Davis : ▁A ▁Biography ▁and ▁Se lections ▁from ▁His ▁Works " ▁( Transaction ▁Publish ers , ▁ 2 0 0 5 ) ▁ ▁External ▁links ▁Kings ley ▁Davis ▁at ▁Encyclop ædia ▁Britannica ▁Ob itu ary ▁at ▁Stan ford ▁News ▁Biography ▁at ▁the ▁American ▁Soci ological ▁Association ▁Biography ▁from