Agile software development is a style of software development which aims to achieve customer satisfaction through a continuous delivery of smaller deliverables.
Active Customer Involvement
Priority based delivery
Waterfall methodology gets it's name from it's sequential nature. As illustrated below, the software development process is seen as an iterative process where software moves from step to step until reaching the end.
David West of Forrester Research conducted a study about agile development in the workplace today. His conclusion was that although Agile and Scrum were the most popular methodologies organizations reported using, upon closer inspection, most organizations utilized a hybrid of methodologies. PC Paramedics believes that no one methodology will fit every organization, team and project. The reality is certain aspects of methodologies may not fit well into your organization. PC Paramedics utilizes the principles and ideas of the methodology where it applies.
I suppose it is tempting, if the only tool you have is a hammer, to treat everything as if it were a nail.
-- Abraham Maslow