The NAC market is forecasted to grow substantially through 2018, reaching $1.46 billion. Top vendors currently control 70% of the market. Key drivers of NAC adoption include the ability to quarantine endpoints, support for BYOD, malware detection capabilities, ease of use, and integration with other security tools. The financial, government, healthcare, and education sectors account for 80% of NAC sales. NAC solutions must address challenges like interoperability, mobile workforce deployment, scalability, and streamlining IT operations like guest access and device management. The future of NAC involves more cohesive, distributed defenses that seamlessly integrate endpoint and perimeter security.