Agile and Waterfall are two widely used project management methodologies, each suited for specific scenarios
http://loft.awardspace.info/smf/index.php?PHPSESSID=0ab2b6624bd473367a57db55f241060d&action=profile;u=265313. Waterfall follows a linear, sequential process where each phase (e.g., design, development, testing) is completed before moving to the next. It works well for projects with clear, unchanging requirements, like construction or manufacturing.