  I discuss the mere 5 % of atoms in the cosmic energy pie. It is basically the
chiral matter problem. Then, I review the chiral matter problem from a grand
unification (GUT) point of view, and point out that anti-SU(N), easily
implementable in string compactification, is a possibility. Here `anti-' means
that the GUT group breaking is through the anti-symmetric tensor field(s), e.g.
<\Phi^{[AB]}>= <\Phi_{[AB]}>. We argued for an anti-SU(7) [= SU(7) x U(1)]
families-unification model from a Z(12-I) orbifold compactification. The
Z(12-I) orbifold is briefly discussed and the multiplicity 2 in the T3 twisted
sector is the key obtaining three chiral families. Yukawa coupling structure is
shown to be promising. A numerical study shows that the anti-SU(7) model
satisfies the CKM fit. It is shown that the doublet-triplet splitting is
obtained naturally, where the dominant process for proton decay is by the
exchange of GUT scale gauge bosons such that proton to pi-zero plus positron is
the dominant channel.
