BibTeX recognises a bewildering array of name prefixes (mostly those deriving from European language names); it ignores the prefixes when sorting the bibliography - you want "Ludwig van Beethoven" sorted under "Beethoven", not under "van". (Lamport made a witty deliberate mistake with Beethoven's name, in the first edition of his LaTeX manual.)
However, a recurring issue is the desire to quote Lord Rayleigh's publications ("Lord" isn't an acceptable prefix), or names from languages that weren't considered when BibTeX was designed such as "al-Wakil" (transcribed from the Arabic). What's needed is a separate "sort key", but BibTeX only allows such a thing in citations of items that have no author or editor.
The solution is to embed the sort key in the author's name, but to
prevent it from being typeset. Patashnik recommends a command
\noopsort (no-output-sortkey), which is defined and used as
follows:
@PREAMBLE{ {\providecommand{\noopsort}[1]{}} }
...
@ARTICLE{Rayleigh1,
AUTHOR = "{\noopsort{Rayleigh}}{Lord Rayleigh}",
...
This question on the Web: http://www.tex.ac.uk/cgi-bin/texfaq2html?label=bibprefixsort