Trixie,
I went to a local bike shop and went window shopping after I did some on line research. I wanted a red bike that was comfortable, at the time. Now I ride a road bike, not quite as comfy, but it is red .

When I went to the shops, I talked a lot to the folks there and if I didn't like one person, I tried on another day or went to a different shop. I looked at all of the different types of bikes, they have bikes just for road, bikes just for dirt, combination bikes, and what they're calling comfort bikes for the new casual riders. If you're racing for a long period of time, weight and comfort are important. Also, it must be fitted to you.

I researched www.trek.com just to see the different types of bikes that they have. They have a cool wizard that asks you a bunch of questions and then suggests a style of bike and several alternatives. That's how I knew what to look for at the shop.

I also looked at other web sites for bikes, I started by typing bicycles in my search engine and went from there. I was too impatient to wait for a book. Good luck. Let us know what you end up with.

By the way, what's a duathon?