The Kim Philby - Oleg Kalugin Collection consists of five letters from Philby to Kalugin and three typed manuscripts written by Philby. In the letters, Philby expresses his friendship for Kalugin and mentions mutual acquaintances. The manuscripts, for their part, concern counterintelligence. They are typed with a few handwritten notations. The Kim Philby - Oleg Kalugin Collection is preserved in one small archival box (0.25 linear feet).