We are all a little guilty of watching these Espionage television series. How well do producers capture the day to day life of CIA, FBI, or NSA agent? Producers sometimes work with government agents to produce a eye catching t.v shows filled with action, drama, romance, and revenge. Producers make a perfect balance of fact and maybe a little fiction when making a television series.
During the war agents would communicate by writing harmless letters to friend, but they write special messages on the envelope. There are generally three kinds of invisible ink: those developed by heat, those developed by light, and those developed by chemical reactions. Axis powers responded by developing 'dry ink' and hiding packets of it in care packages. Upon discovery of the packets with another round of creative chemistry to develop new papers with sensitivity to fluid and dry inks. Products used to make the ink included Food like honey, milk, sugar solutions, and clear colas were also developed by heat, and could be used by civilians. Even soapy water worked.

Popov is one of the first agent to pop up in "Double Cross" he is described as playboy and womanizer. Popov was born in 10 July 1912 in Titel, Austro-Hungary (now Serbia), to a wealthy Serbian family.He spoke German, French, English and Italian and was well versed in culture.Once accepted as a double agent, Popov moved to London. His international business activities in an import-export business provided cover for visits to neutral Portugal, which was linked to the UK by a weekly civilian air service for most of the war. Popov fed enough MI5-approved information to the Germans to keep them happy and unaware of his actions (He secretly hated the Nazi party). The assignments given to him were of great value to the British in assessing enemy plans and thinking. Over the years Popov had many girlfriends and scandals affairs, he lived an extravagant  life style  sending most of the money he earned. It is said that James Bond was      based off of this double agent. Below are pictures with Popov and his girlfriends