  We describe the development of the LHAPDF library from its initial
implementation following the Les Houches meeting in 2001 to its present state
as a functional replacement for PDFLIB. Brief details are given of how to
install and use the library together with the PDF sets available. We also
describe LHAGLUE, an add-on PDFLIB look-a-like interface to LHAPDF, which
facilitates using LHAPDF with existing Monte Carlo generators such as PYTHIA
and HERWIG.
