The rotation curves of spiral galaxies are crucial for understanding their mass distribution, dynamics, evolution, and formation. This review covers various methods to derive rotation curves and discusses the characteristics of observed curves in relation to galaxy properties such as Hubble type, structure, activity, and environment. The historical introduction traces the development of rotation curve studies from early observations in the 1910s to modern techniques using high-resolution optical, radio, and millimeter-wave observations. The review highlights the importance of emission lines like H$\alpha$, HI, and CO for deriving mass distributions, especially in the inner regions of galaxies. It also discusses the challenges and limitations of different observational methods, including intensity-weighted velocity, centroid-velocity, peak-intensity-velocity, and envelope-tracing methods. The central rotation curves of galaxies are particularly intriguing, with some massive galaxies showing high-velocity peaks near the nucleus, possibly due to massive black holes. The review explores the impact of nuclear activity, resonance rings, nuclear warps, and counterrotation on rotation curves. Finally, it examines the statistical properties of rotation curves, environmental effects in clusters, and lopsided position-velocity diagrams, emphasizing the need for further studies to understand the complexities of spiral galaxy kinematics.The rotation curves of spiral galaxies are crucial for understanding their mass distribution, dynamics, evolution, and formation. This review covers various methods to derive rotation curves and discusses the characteristics of observed curves in relation to galaxy properties such as Hubble type, structure, activity, and environment. The historical introduction traces the development of rotation curve studies from early observations in the 1910s to modern techniques using high-resolution optical, radio, and millimeter-wave observations. The review highlights the importance of emission lines like H$\alpha$, HI, and CO for deriving mass distributions, especially in the inner regions of galaxies. It also discusses the challenges and limitations of different observational methods, including intensity-weighted velocity, centroid-velocity, peak-intensity-velocity, and envelope-tracing methods. The central rotation curves of galaxies are particularly intriguing, with some massive galaxies showing high-velocity peaks near the nucleus, possibly due to massive black holes. The review explores the impact of nuclear activity, resonance rings, nuclear warps, and counterrotation on rotation curves. Finally, it examines the statistical properties of rotation curves, environmental effects in clusters, and lopsided position-velocity diagrams, emphasizing the need for further studies to understand the complexities of spiral galaxy kinematics.