This book provides a broad overview of emerging digital threats and computer crimes, with an emphasis on cyber-stalking, hacktivism, fraud and identity theft, and attacks on critical infrastructure. It also analyzes the online underground economy, digital currencies, and cybercrime on the Dark Web. The book explores how Dark Web crimes are conducted in new mediums, such as IOT and P2P file sharing systems. It starts with the fundamentals of Dark Web and explains the threat landscape of Dark Web. After introducing the TOR browser, it takes a deep dive into cybersecurity criminal activities in the Dark Web, forensics of Dark Web, web content analysis, and threat intelligence.