This paper is designed to help users who would like to understand virtualization better in order to evaluate the operational benefits it could provide. While the term "virtualization" is far from new, it can mean different things to different people--and indeed often goes undefined. This paper, while focused on the HP StorageWorks EVA4400 as an example, aims to lay out the basics in a straightforward and not overly-technical manner. It will concentrate more on the value virtualization brings to data centers and businesses than on the intricacies of how it is achieved. To do this, it will introduce virtualization generically, and then examine its implementation and value at both the server and storage levels (also covering how those are linked). Tthe paper specifically examines where, how and for whom the EVA4400 from HP can best fit.