Market segmentation s a natural result of the vast differences among people

It is relatively easy to design for the perfect cases, when everything goes right, or when all the information required is available in proper format

Scientists are always skeptics.

Readers always seem to think that the author has some control over the design of their books.

Knowing how people will use something is essential

The designer has an obligation to provide an appropriate conceptual model for the way that the device works. It doesn't have to completely accurate but it has to be sufficiently accurate that it will help in both the learning of the operation and also dealing with novel situations.

Everyday people are not very good designers.