The Binary File Descriptor library (libbfd) provides a common interface for reading and parsing all popular binary formats, compiled for a wide variety of architectures. The BFD library is part of the GNU project and is used by many applications in the binutils suite, including objdump, readelf, and gdb.

As part of the book "Practical Binary Analysis " , It's helping the reader to create its very common linux tools such this project. It's intended for use in static analysis tools. Note that this is completely different from the dynamic loader provided by the OS, whose job it is to load binaries into memory to execute them.