This paper presents a study of string-generated gravity models, focusing on the Gauss-Bonnet term as the leading quadratic curvature correction to the Einstein action. The model is shown to have both flat and anti-de Sitter space as solutions, but the cosmological branch is unstable due to the presence of a ghost graviton. The general static spherically symmetric solution is asymptotically Schwarzschild, and the sign of the Gauss-Bonnet coefficient determines whether a normal event horizon or a naked singularity exists. The model is shown to solve its own cosmological constant problem in an elegant way. The action includes the Einstein and Gauss-Bonnet terms, and the field equations are derived. The solutions include both asymptotically flat and anti-de Sitter branches. The anti-de Sitter branch is unstable, as the graviton excitations about this background are ghosts. The model is also analyzed in the presence of higher-order curvature corrections and an explicit cosmological term, with similar conclusions. The field equations are solved for spherically symmetric solutions, which are shown to reduce to the Schwarzschild solution in the Einstein limit. The solutions have a positive gravitational mass or a negative gravitational mass, depending on the branch. The anti-de Sitter branch is shown to have a naked singularity at the origin, while the flat branch has no horizons. The paper also discusses the implications of the Gauss-Bonnet term for the stability of the solutions and the role of the cosmological constant. It is shown that the Gauss-Bonnet term does not affect the propagator or distort plane-wave solutions, and that higher-order corrections do not spoil the asymptotically flat branch. The paper concludes that the Gauss-Bonnet term is essential for the stability of the model and that the model solves the cosmological constant problem in an elegant way.This paper presents a study of string-generated gravity models, focusing on the Gauss-Bonnet term as the leading quadratic curvature correction to the Einstein action. The model is shown to have both flat and anti-de Sitter space as solutions, but the cosmological branch is unstable due to the presence of a ghost graviton. The general static spherically symmetric solution is asymptotically Schwarzschild, and the sign of the Gauss-Bonnet coefficient determines whether a normal event horizon or a naked singularity exists. The model is shown to solve its own cosmological constant problem in an elegant way. The action includes the Einstein and Gauss-Bonnet terms, and the field equations are derived. The solutions include both asymptotically flat and anti-de Sitter branches. The anti-de Sitter branch is unstable, as the graviton excitations about this background are ghosts. The model is also analyzed in the presence of higher-order curvature corrections and an explicit cosmological term, with similar conclusions. The field equations are solved for spherically symmetric solutions, which are shown to reduce to the Schwarzschild solution in the Einstein limit. The solutions have a positive gravitational mass or a negative gravitational mass, depending on the branch. The anti-de Sitter branch is shown to have a naked singularity at the origin, while the flat branch has no horizons. The paper also discusses the implications of the Gauss-Bonnet term for the stability of the solutions and the role of the cosmological constant. It is shown that the Gauss-Bonnet term does not affect the propagator or distort plane-wave solutions, and that higher-order corrections do not spoil the asymptotically flat branch. The paper concludes that the Gauss-Bonnet term is essential for the stability of the model and that the model solves the cosmological constant problem in an elegant way.