Since zero is the lowest value of an unsigned binary integer,
which is one of the most fundamental types in programming and
hardware design, it is often natural to count from zero rather
than one, especially when the integer is actually an index, as
in hardware addressing or c and lisp's 0-based indexing of
arrays. Hackers and computer scientists often like to call the
first chapter of a publication "Chapter 0", especially if it is
of an introductory nature (one of the classic instances was in
the First Edition of k&r). In recent years this trait has also
been observed among many pure mathematicians (who have an
independent tradition of numbering from 0). Zero-based numbering
tends to reduce fencepost errors, though it cannot eliminate
them entirely. Logically, the next item after the zeroth should
be the "oneth" but this is never used.