  We are considering the semi-classical string soliton solution of Gubser,
Klebanov and Polyakov which represents highly excited states on the leading
Regge trajectory, with large spin in $AdS_5$. A prescription relates this
soliton solution with the corresponding field theory operators with many
covariant derivatives, whose anomalous scaling dimension grows logarithmically
with the space-time spin. We explicitly derive the dependence of anomalous
dimension on spin for all leading and next-to-leading orders at strong
coupling. We develop an iteration procedure which, in principle, allows to
derive all terms in the large spin expansion of the anomalous scaling dimension
of twist two operators. Our string theory results are consistent with the
conjectured "reciprocity" relation, which has been verified to hold in
perturbation theory up to five loops in N=4 SYM. We also derive a duality
relation between long and short strings.
