This document discusses insider threats and recommendations to address them. It notes that insider threats remain the top counterintelligence challenge, as the most damaging failures in US history were caused by trusted insiders. Insiders are motivated by ideology, money, sex, or blackmail. They operate undetected for years on average before being caught, increasing damage over time. Effective insider threat programs are needed to proactively identify threats before they fully mature. The FBI recommends screening new employees carefully, ongoing security training, anonymous reporting systems, protecting information adequately, monitoring networks, and ensuring security teams have needed tools. Network analytics can help detect insider threats by monitoring activity.