Alex Ionescu is the founder of Winsider Seminars & Solutions Inc.,specializing in low-level system software for administrators and developers aswell as reverse engineering and security training for various organizations.He was a coauthor of the Windows Internals series for the last two editions.From 2003-2007, Alex was the lead kernel developer for ReactOS, an open sourceclone of Windows XP/Server 2003 written from scratch, for which he wrote mostof the Windows NT-based kernel. During his studies in Computer Science, Alexworked at Apple on the iOS kernel, boot loader, firmware, and drivers on theoriginal core platform team behind the iPhone, iPad, and AppleTV. Returning tohis Windows security roots, Alex is now Chief Architect at CrowdStrike, asecurity start-up focused on nation-state adversaries and other highlysophisticated actors. Alex continues to be very active in the securityresearch community, discovering and reporting several vulnerabilities relatedto the Windows kernel and presenting talks at conferences such as Black Hat,SyScan, and Recon. His work has frequently led to the discovery ofkernel/firmware/hypervisor vulnerabilities and design flaws, as well as todozens of non-security bugs.