This review presents recent breakthroughs in the nonlinear Hall (NLH) effect, emphasizing theoretical foundations and experimental progress. The NLH effect arises from the Berry curvature dipole (BCD), a geometric property of materials with broken inversion symmetry. The BCD is crucial for the nonlinear Hall response, which can be intrinsic or extrinsic. Theoretical models and candidate materials with tunable BCD are discussed, along with experimental reports on measuring NLH effects in various materials. The review also highlights other nonlinear effects, such as the nonlinear planar Hall, anomalous Hall, and spin/valley Hall effects. It concludes with an outlook on open questions and challenges in this rapidly evolving field. The NLH effect can occur in time-reversal symmetric systems, unlike the conventional Hall effect, which requires time-reversal symmetry breaking. The BCD is a key factor in the NLH response, and its role is analyzed in both quantum and semiclassical frameworks. The review discusses the interplay between disorder scattering and the NLH response, as well as the symmetry-based indicators for the emergence of NLH effects. It also explores the third-order Hall effect and its connection to the Berry connection polarizability tensor. The NLH effect has been observed in various materials, including 2D Dirac models and topological insulators, and its significance in quantum computing and other applications is highlighted. The review provides a comprehensive overview of the current state of research on the NLH effect, emphasizing its theoretical and experimental importance.This review presents recent breakthroughs in the nonlinear Hall (NLH) effect, emphasizing theoretical foundations and experimental progress. The NLH effect arises from the Berry curvature dipole (BCD), a geometric property of materials with broken inversion symmetry. The BCD is crucial for the nonlinear Hall response, which can be intrinsic or extrinsic. Theoretical models and candidate materials with tunable BCD are discussed, along with experimental reports on measuring NLH effects in various materials. The review also highlights other nonlinear effects, such as the nonlinear planar Hall, anomalous Hall, and spin/valley Hall effects. It concludes with an outlook on open questions and challenges in this rapidly evolving field. The NLH effect can occur in time-reversal symmetric systems, unlike the conventional Hall effect, which requires time-reversal symmetry breaking. The BCD is a key factor in the NLH response, and its role is analyzed in both quantum and semiclassical frameworks. The review discusses the interplay between disorder scattering and the NLH response, as well as the symmetry-based indicators for the emergence of NLH effects. It also explores the third-order Hall effect and its connection to the Berry connection polarizability tensor. The NLH effect has been observed in various materials, including 2D Dirac models and topological insulators, and its significance in quantum computing and other applications is highlighted. The review provides a comprehensive overview of the current state of research on the NLH effect, emphasizing its theoretical and experimental importance.