Tourism holds a place of prominence in economic development. The book aims to guide and support the readers through the complexities of the economic impact of tourism in the 21st century. It covers important principles and concepts that are supported by research and evidence from economics and other behavioural sciences. The degree of reliance of local economy on tourism has a statistically significant impact on the level of the capital outlays, transportation, Police protection, protection from natural disasters, Parks and recreation, financial administration and public expenditure. The book presents a comprehensive overview of history and global development of tourism, often considered the largest industry in the world today. Tourism is one of the most flourishing industry, both on the macro and micro level. Because of its high forward and backward linkage and heavy employment generation capacity, government policies across the globe have focused on this avenue. India with its rich natural beauty and a strong historical background aspire to be the hotspot in the international tourist map. In India the Himalayan belt has always been a favourable tourist destination. The unplanned heavy influx of tourists has converted favourable tourists destination to be Sikkim, Arunachal Pradesh, Laddakh, Uttarakhand etc. The book is an outline on the economic, social and cultural issues of tourism in the Mountain region. It provides a detailed study on the economic impact in different regions of Sikkim for sustainable management and environmental protection. The target audience of this book is not limited to diploma degree holders, students of management and researchers, it would also be beneficial for the Ministry of Tourism of Sikkim, the planners, the policy-markets and India in general.