Many wells and reservoirs are prematurely abandoned due to excess water production, resulting in lost production and recovery. We need ways to delay water production in new fields, and to maximize efficiency in mature producing fields. This talk highlights some of the latest technology in prevention, diagnosis, mechanical/chemical methods, and with supporting field case history. Specific applications for injector, producer, reservoir-wide, and facility-related will be communicated. New near-wellbore and reservoir in-depth treatments will be particularly detailed. There will be discussions on Best Practices/ Lessons Learnt to improve the success rates, and mention of challenges ahead.