At equivalue at its core, Agile isnít so much a methodology as a philosophy. Itís a blanket term for an approach to project management that prioritizes incremental, feedback-driven changes into software development. (Weíll get into the methodologies and how to actually use Agile later on).
To understand why Agile works so well, we need to do a bit of a history lesson. Until the last few decades, the Waterfall method was the prevailing way software (and most products) were developed. This meant spending a huge amount of time and effort upfront gathering resources and planning with a lot of key decisions based purely on assumption.