This course is the first in a series to cover USB in depth. Throughout the series, emphasis will be placed on USB mass storage devices which are nearly always a part of forensic investigations. USB Human Interface Devices (HID) will also be discussed as they are used in a number of attacks. This course covers the fundamentals of how USB devices interact with hosts. The course should be valuable not only to forensics and information security professionals, but to anyone wanting a deeper understanding of how USB works under the covers.