This paper explores the semi-classical limit of the gauge/string correspondence, focusing on string theories dual to four-dimensional gauge theories. The authors apply a world-sheet sigma model approach to identify semi-classical soliton solutions that correspond to highly excited string states in the gauge theory, particularly those with small anomalous dimensions. The simplest class of such states are strings on the leading Regge trajectory in $AdS_5$, which correspond to operators with many covariant derivatives. These operators exhibit logarithmic scaling violations in their anomalous dimensions, similar to those found in perturbation theory. The paper also discusses other examples of highly excited string states, such as strings spinning on $S^5$ and oscillating strings, and extends the analysis to states with arbitrary conformal dimensions. The results highlight the connection between stringy effects in the AdS/CFT duality and the behavior of gauge theory operators, particularly in the context of high-spin operators. The authors argue that the semi-classical methods used can be applied to a broader class of operators and backgrounds, providing insights into the strong coupling regime of gauge theories.This paper explores the semi-classical limit of the gauge/string correspondence, focusing on string theories dual to four-dimensional gauge theories. The authors apply a world-sheet sigma model approach to identify semi-classical soliton solutions that correspond to highly excited string states in the gauge theory, particularly those with small anomalous dimensions. The simplest class of such states are strings on the leading Regge trajectory in $AdS_5$, which correspond to operators with many covariant derivatives. These operators exhibit logarithmic scaling violations in their anomalous dimensions, similar to those found in perturbation theory. The paper also discusses other examples of highly excited string states, such as strings spinning on $S^5$ and oscillating strings, and extends the analysis to states with arbitrary conformal dimensions. The results highlight the connection between stringy effects in the AdS/CFT duality and the behavior of gauge theory operators, particularly in the context of high-spin operators. The authors argue that the semi-classical methods used can be applied to a broader class of operators and backgrounds, providing insights into the strong coupling regime of gauge theories.