This book offers a detailed description of the geology, geochemistry and deposit model of key deposits in the Mianning-Dechang REE belt in West Sichuan, one of the most important REE belts in the world and genetically related to the Himalayan carbonatite-alkaline complex, helping readers to understand the ore-forming process of carbonatite-related REE deposits. The carbonatite-related REE deposits provide more than 90% of worldwide LREE resources. Thanks to the deposit model presented here, it can serve as an important guidebook for REE exploration and will be of interest to various members of industry and academia, including those who work in exploration, research and teaching. The methods for inclusion studies and petrochemistry discussed represent the cutting edge of analytical techniques in geology.