Landslides are common disaster phenomena in many countries causing great economic losses. The Darjiling-Sikkim Himalayas in India is known to be the most severely affected. Even a glance at landslide statistics gives some idea of the enormity of damage done and the ever present threat to lives and property. It has been observed that even 50 mm of rainfall in an hour would cause landslips. Unauthorized structures in the unsafe zones, absence of an adequate drainage system and unplanned growth of settlements have accelerated the process of ecological imbalance. In recognition of the acuteness of problems related to landslides, this paper summarizes our knowledge of slope stability so as to provide information on the origin of slope movements and the methods of their investigation, prevention and control. A series of case studies in the Darjiling-Sikkim Himalayas have been undertaken to provide a better understanding of this acute natural disaster problem.