Design analysis
Structural design
Appearance and behavior
Navigation and controls
Usability / acceptability

Design analysis
Current interface design practice is characterized by heavy emphasis on analysis of the users, tasks and context in which the interface must function. In participatory design, the analysis may be conducted as part of the design process itself, with target users for a product working as members of the design team.	User and Task Analysis for Interface Design by Joann T. Hackos & Janice C. Redish The basic how-to book of choice for professionals. back to the top

Structural design

Before you can design the appearance and behavior of an interactive product, you have to design the underlying structure of it ... how will its parts relate to one another? which parts will be linked to which others? given the kinds of things people need to do with it, how should it be organized behind the scenes? Sometimes this part of the design is refered to as the engineer or designer's mental model of a program -- how do the people who create the program think it is organized?

Information Architecture for the World Wide Web by Louis Rosenfeld, Peter Morville One of the best explanations you can find for the concept of information structure - read it even if you're not designing for the Web. back to the top

Appearance and behavior

When people think about interfaces, they usually think of this aspect first -- because this is the part that we actually interact with! The way an interface makes itself know to us -- visual displays, sounds, size, shape, smell, changes in our environment -- all the tangible evidence that something is there to interact with us, and all the elements that let us know what can be done with the thing constitute its interface.     In the process of design, multiple appearances and behaviors are considered and judged for their ability to communicate the appropriate functions to the users of a product. Since these are the tangible parts of a product, they are called the "form."

Designing Visual Interfaces : Communication Oriented Techniques by Kevin Mullet & Darrell Sano The most complete and sensible book there is explaining the reasons that good interface design is good. back to the top

Navigation and controls

The majority of current interfaces are visually-based, although audio interfaces, audio-enhanced interfaces, and gestural interfaces are being designed at a rapid pace. The computer icon is a familiar kind of control for many computer users today, as are buttons, scroll bars, and a range of other "widgets."     Navigation is the metaphorical term used to describe users controlling the sequence of displays in a program -- the metaphor is so useful that people say "go back to that other screen," and "I got lost after I clicked on that button and it brought me here" without thinking consciously about it.     Navigation is sometimes boiled down to three major concerns for users: where am I now? where can I go from here? how can I get back to where I was?     The Gallery of Examples by Sonny Kirkley and Elizabeth Boling contains examples of many kinds of visual interface controls.

The Icon Book : Visual Symbols for Computer Systems and Documentation by William Horton Icons are only one type of interface control but they are an important one and this is the most complete general reference there is for designing them. back to the top

Usability / acceptability

In the competitive world of software design, it's not enough to follow good design principles and create something the designer likes or finds useful. The designer is almost never the same kind of person as the people who are going to be the users of a program -- designers have borrowed research techniques from the social sciences to help themselves find out how acceptable their designs are going to be in the real world with the real people who have to use them.     Usability testing is not carried out to find the technical problems with software -- usability testing is conducted to find out if the software is easy to learn and use, effective for the job it is supposed to do, and acceptable in all ways to the people who will use it.     The Alert Box, Jakob Nielsen's bi-weekly column devoted to Web site usability, illustrates a wide range of usability issues to be considered by interface designers. Similar issues - and many of the same ones - affect designers of any interface.

Usability Engineering by Jakob Nielsen This is the definitive academic text on usability. Handbook of Usability Testing by Jeff Rubin This is the how-to book -- if you plan to test a product for usability, you need this book. back to the top