Espionage techniques involve various methods used to gather secret information from individuals, organizations, or governments. Common techniques include surveillance, where operatives observe targets discreetly, and interception, which involves capturing communications like emails or phone calls. Another technique is infiltration, where spies gain access to secure locations or groups to collect intelligence. Additionally, deception can be employed, using false identities or misinformation to manipulate targets. These methods are often used in the context of national security and corporate competition.