Effectively containing and controlling wildfires is a paramount goal for fire management agencies. This review, presented in two parts, delves into the complex realm of wildfire suppression effectiveness. The first part discusses research conducted at the flame and Fireline scales, shedding light on critical aspects of suppression efforts. The second part broadens the perspective, addressing effectiveness at incidents and scales of landscape and highlighting the motivation and implications of these studies, Recent findings reveal that wildfire suppression research encompasses various approaches. Laboratory experiments conducted at the flame size help evaluate the efficacy of suppression chemicals, aiding in resource selection. Field observations at the Fireline scale provide a realistic assessment of wildfire conditions, allowing for the examination of resource productivity and the impact of suppression efforts on fire behavior, Assessing wildfire suppression effectiveness is challenging due to diverse objectives, dynamic variables, and data acquisition hurdles. However, recent case studies underscore the advantages of fuel management in enhancing suppression effectiveness, while economic analyses offer insights into resource contributions during containment. Nevertheless, productivity models derived from non-wildfire data often overpredict operational productivity. Defining and measuring wildfire suppression effectiveness varies depending on scale and purpose. From flames to landscapes, each scale presents unique opportunities and challenges. Despite the complexities, ongoing research illuminates key variables and contributes to a deeper understanding of effective wildfire suppression.