The foundation of good interface design is INTELLIGENT BORROWING. That is, you should be building your design on other people's good work rather than coming up with your own design ideas. Borrowing is important for three distinct reasons. First, given the level of quality of the best user interfaces today, it's unlikely that ideas you come up with will be as good as the best ideas you could borrow. Second, there's a good chance, if you borrow from the right sources, that many of your users will already understand interface features that you borrow, whereas they'd have to invest in learning about features you invent. Finally, borrowing can save you tremendous effort in design and implementation and often in maintenance as well.

HyperTopic: "Won't I get sued if I follow your advice?"

As you read through this chapter you'll realize that much of the borrowing we recommend is not only allowed, it's actually encouraged by the developers of the original system. Apple Computer, for example, provides style guides, software toolkits, and other support for developers who want to produce Macintosh programs that look and act similar to all the other Macintosh programs.

In addition, there are a lot of other things you can copy without infringing on the rights of other companies. Unfortunately, there's no clear and simple rule that defines those rights. Appendix L gives an overview of the legal principles and provides a list of "boundary markers," examples of things that can and cannot be legally copied under the current laws. The development process we recommend is to keep those boundary markers in mind, rough out your interface, and then talk over your decisions with your company's attorney. If there's a central feature of the interface you're worried about, such as picking up an entire interface metaphor, you may want to get legal advice a little earlier.

Because the law is always changing (and this area of law is especially unsettled) there are some other things you need to do. One is to read the trade journals and keep yourself abreast of the current state of the law. Another is that your business plans should take into account the possibility that, no matter how careful you are, you may become involved in a lawsuit.