  We provide a non-technical introduction to "misaligned supersymmetry", a
generic phenomenon in string theory which describes how the arrangement of
bosonic and fermionic states at all string energy levels conspires to preserve
finite string amplitudes even in the absence of spacetime supersymmetry.
Misaligned supersymmetry thus naturally constrains the degree to which
spacetime supersymmetry can be broken in string theory while preserving the
finiteness of string amplitudes, and explains how the requirements of modular
invariance and absence of physical tachyons affect the distribution of states
throughout the string spectrum.
