Klaus Fuchs masanin kimiyyar lissafi dan kasar Jamus ne wanda ya kasance jigo wajen kera makaman nukiliya ga Amurka da Tarayyar Soviet a lokacin yakin cacar baka. Ya kuma kasance ɗan leƙen asiri na Tarayyar Soviet, inda yake isar da muhimman bayanai game da fasahar nukiliya ga hukumar leƙen asirin Soviet. Daga karshe an kama Fuchs kuma aka same shi da laifin leken asiri, kuma ya yi shekara tara a gidan yari na Burtaniya kafin a sake shi ya koma Jamus ta Gabas.