The document discusses the booting process of the BeagleBone Black. It begins with an overview of the PC and BeagleBone booting processes. It then covers booting through an SD card, including partitioning and creating a root filesystem. The document introduces bootloaders like U-Boot, describes serial booting, and how to add commands to U-Boot. It provides hands-on examples of bringing up the BeagleBone board from recovery.