If someone had told me that our world was going to be taken over by small devices back in 1995, I would have laughed. Then technology started moving in new directions—one of which was into cell phones. Cell phones not only take pictures but let me send those pictures to my mom if I so desire. The world that opened up was one that enables people in many new, interesting and, sometimes, annoying ways. I'm still not sure I really want to get my email on my phone. After all, that seems to imply I should answer it right away, doesn't it? At the first meeting of the minds on the Mobile Information Device Profile (MIDP), in January 2000, the issue of needing a style guide for this new technology was raised. Even then, all of us knew that if MIDP became successful, it would require a concerted effort from all the players: content providers, handset manufacturers, and operators. A style guide would help make that happen. It took much longer than we expected to get the first version of the style guide out on the web. That's why, once the MIDP 2.0 effort began, we started planning for the second version of the style guide. It still took longer than we thought to get this tutorial out. Murphy's Law works in mysterious ways. We hope this tutorial will educate our readers about MIDP as well as about user-experience issues. Creating great user interfaces is still as much science as it is art, and vice versa. If this tutorial enables great MIDlets, it will be a success. The focus here is on giving you as much advice as we can about what works and what doesn't work. Every domain has its idiosyncrasies and consumer user interface design is no different. If my company buys me a laptop and I don't like it, I grumble but use it. If I buy myself a cell phone and don't like it, it goes back to the store and I get my money back. That fundamental difference significantly changes people's motivation for what they will put up with. If you remember nothing else, remember that.