A boot loader is the first software program that runs when a computer starts. It is responsible for loading and transferring control to the OperatingSystem Kernel.
A multiboot loader offers a menu and the ability to select from a list of operating systems.
Multiboot loaders include:
You can chain bootloaders, so for example, grub can then call Windows' bootloader (this is the preferred method for DualBooting Linux and Windows.)
11 pages link to BootLoader: