▁early ▁work ▁was ▁in ▁c ob ord ism ▁theory , ▁in ▁relative ▁isol ation . ▁Among ▁other ▁adv ances ▁he ▁showed ▁how ▁the ▁Adams ▁spectral ▁sequence , ▁a ▁powerful ▁tool ▁for ▁proceed ing ▁from ▁hom ology ▁theory ▁to ▁the ▁calculation ▁of ▁hom ot opy ▁groups , ▁could ▁be ▁adapted ▁to ▁the ▁new ▁( at ▁that ▁time ) ▁coh om ology ▁theory ▁typ ified ▁by ▁c ob ord ism ▁and ▁K - theory . ▁This ▁required ▁the ▁development ▁of ▁the ▁idea ▁of ▁coh om ology ▁operations ▁in ▁the ▁general ▁setting , ▁since ▁the ▁basis ▁of ▁the ▁spectral ▁sequence ▁is ▁the ▁initial ▁data ▁of ▁Ext ▁fun ctors ▁taken ▁with ▁respect ▁to ▁a ▁ring ▁of ▁such ▁operations , ▁general ising ▁the ▁Ste en rod ▁algebra . ▁The ▁resulting ▁Adams – Nov ik ov ▁spectral ▁sequence ▁is ▁now ▁a ▁basic ▁tool ▁in ▁stable ▁hom ot opy ▁theory . ▁ ▁Nov ik ov ▁also ▁carried ▁out ▁important ▁research ▁in ▁geometric ▁topology , ▁being ▁one ▁of ▁the ▁pione ers ▁with ▁William ▁Brow der , ▁Dennis ▁S ull ivan ▁and ▁Terry ▁Wall ▁of ▁the ▁surg ery ▁theory ▁method ▁for ▁class ifying ▁high - dimensional ▁manif olds . ▁He ▁proved ▁the ▁topological ▁in var iance ▁of ▁the ▁rational ▁Pon try agin ▁classes , ▁and ▁pos ed ▁the ▁Nov ik ov ▁conject ure . ▁This ▁work ▁was ▁recogn ised ▁by ▁the ▁award ▁in ▁ 1 9 7 0 ▁of ▁the ▁Field s ▁Medal . ▁He ▁was ▁not ▁allowed ▁to ▁travel ▁to ▁Nice ▁to ▁accept ▁his ▁medal . ▁He ▁received ▁it ▁in ▁