Computer graphics fall into two main categories, bitmap graphics and vector graphics. You learned about creating and manipulating bitmap images in the Photoshop tutorial. Adobe Illustrator is a vector based software package. Drawing programs such as Illustrator create vector graphics made of lines and curves, defined by mathematical objects called vectors. A vector graphic is resolution-independent! What this means for you is that unlike bitmap images, a vector based piece of artwork can be scaled to any size and printed on any output device at any resolution without losing its detail or clarity. Vector graphics are the best choice for type, and bold graphics that need to maintain their crispness at various scales.