Bose-Einstein statistics is the statistical mechanics of a system
of indistinguishable particles for which there is no restriction
on the number of particles that may simultaneously exist in the
same quantum energy state. 

Bosons are particles that obey Bose-
Einstein statistics, and they include photons, pi mesons, all
nuclei having an even number of particles, and all particles with
integer spin. 

Fermions (electrons, protons, neutrons) are
particles that obey the Pauli exclusion principle: i.e., no two
fermions of the same kind can occupy the same quantum state.

In particle physics, string theory is a theory of elementary
particles based on the idea that the fundamental entities are not
point-like particles but finite lines (strings), or closed loops
formed by strings, the strings one-dimensional curves with zero
thickness and lengths (or loop diameters) of the order of the
Planck length of 10^(-35) meters. 

The fundamental forces comprise
the gravitational force, the electromagnetic force, the nuclear
strong force, and the nuclear weak force, and the "grand unified
theories" are theories that aim to provide a mathematical frame-
work in which the electromagnetic forces, strong forces, and weak
forces emerge as parts of a single unified force, with the three
forces related by symmetry. 

Supersymmetry is an aspect of an
extension of the grand unified theories, an attempt to unify all
the four fundamental forces, i.e., linking gravitation to the
electromagnetic force, the strong force, and the weak force
through a supersymmetry scheme, and superstrings are strings in
this scheme that obey supersymmetry. ... 

... John H. Schwarz
(California Institute of Technology, US) presents a brief
overview of some of the advances in understanding super-
string theory that have been achieved in the last few years.
String theories that have a symmetry relating bosons and
fermions, called "supersymmetry", are called "superstring"
theories. Major advances in understanding of the physical world
have been achieved during the past century by focusing on
apparent contradictions between well-established theoretical
structures. In each case the reconciliation required a better
theory, often involving radical new concepts and striking exper-
imental predictions. Four major advances of this type were the
discoveries of special relativity, quantum mechanics, general
relativity, and quantum field theory. This was quite an achieve-
ment for one century, but there is one fundamental contradiction
that still needs to be resolved, namely the clash between general
relativity and quantum field theory. Many theoretical physicists
are convinced that superstring theory will provide the answer.
QY: John H. Schwarz, California Inst. of Technology 818-395-6811
(Proc. Natl. Acad. Sci. US 17 Mar 98)

Related Background:

... Membrane theory (M-theory) is a recent extension of string
theory in which the fundamental physical entities are considered
as surfaces in a many-dimensional space (membranes) rather than
as lines or loop elements (open or closed strings). Given all of
the above, some caution is necessary: the translation of a highly
abstract mathematical model of physical reality into non-mathem-
atical language is often an exercise of limited usefulness, and
in this case in particular, we are presenting only the ghost of
the theoretical scheme. String theory was originally invented in
the 1960s as a theory of the strong force, became overshadowed by
the strong force theory of gluons and quarks, then had a revival
in the 1980s -- but with the history more dependent on new work
than on fashion. ... 

... M. Duff (Texas A & M Univ., US), who is
active in string theory and membrane theory, in a review of
various aspects of the history and essentials of string theory
and membrane theory, suggests that future historians may judge
the 20th century as "a time when theorists were like children
playing on the seashore, diverting themselves with the smoother
pebbles or prettier shells of superstrings, while the great ocean
of M-theory lay undiscovered before them." QY: Michael J. Duff,
Texas A & M Univ., Dept. Physics 409-847-9451
(Scientific American February 1998)