The EFI specification is primarily intended for the IA-32 and Itanium architecture-based computers. The EFI specification defines a model for the interface between operating systems and platform firmware. The interface consists of data tables that contain platform-related information, plus boot and runtime service calls that are available to the operating system and its loader. Together, these provide a standard environment for booting an operating system and running pre-boot applications. EFI is an outgrowth of the "Intel Boot Initiative" (IBI) program that began in 1998.*

*[Source: Intel Technologies Initiatives: EFI]

EFI Presentations (PDF)
A selection of slideshow and presentations related to EFI.