Eshelby's inclusion problem of linear isotropic elasticity is applied
to evaluate the elastic strain energies of general spheroidal inclusio
ns with various misfit strains. The strain-energy minimization criteri
on is adopted and difference in elastic constants between the inclusio
n and the surrounding matrix is taken into account. It is found that n
ot necessarily one of the three representative shapes of the spheroid,
i.e., plate, sphere and needle, but also more general oblate and prol
ate spheroids can be the most favorable shape to minimize the strain e
nergy. In addition, some features and characteristics involved in the
inclusion problem are newly found.