The paper by David G. Boulware and S. Deser explores the properties of a gravity model generated by string theory, focusing on the Gauss-Bonnet invariant. They show that this model admits both flat and anti-de Sitter space solutions but is unstable due to the graviton becoming a ghost in the cosmological branch. The authors derive the general static spherically symmetric solution, which is asymptotically Schwarzschild, and discuss the role of the Gauss-Bonnet coefficient in determining whether there is a normal event horizon or a naked singularity. They also examine the effects of higher-curvature corrections and an explicit cosmological term on the stability of the theory. The Gauss-Bonnet term is shown to be crucial in solving the cosmological constant problem elegantly, as it leads to a viable theory with a unique physically acceptable nature for the asymptotically flat branch. The paper concludes with a discussion on the implications of higher-order curvature corrections and the potential for stable anti-de Sitter sectors under specific conditions.The paper by David G. Boulware and S. Deser explores the properties of a gravity model generated by string theory, focusing on the Gauss-Bonnet invariant. They show that this model admits both flat and anti-de Sitter space solutions but is unstable due to the graviton becoming a ghost in the cosmological branch. The authors derive the general static spherically symmetric solution, which is asymptotically Schwarzschild, and discuss the role of the Gauss-Bonnet coefficient in determining whether there is a normal event horizon or a naked singularity. They also examine the effects of higher-curvature corrections and an explicit cosmological term on the stability of the theory. The Gauss-Bonnet term is shown to be crucial in solving the cosmological constant problem elegantly, as it leads to a viable theory with a unique physically acceptable nature for the asymptotically flat branch. The paper concludes with a discussion on the implications of higher-order curvature corrections and the potential for stable anti-de Sitter sectors under specific conditions.