Information architecture is basically a two-part exercise

Lou distills IA to two steps.

  1. First choose the most useful tools and techniques (e.g., card sorting, contextual inquiry) to learn about users' information needs, the characteristics of content, and organizational context and constraints.
  2. With that knowledge in hand, design an information architecture using the subset of all possible architectural components (e.g., site index, search engine) that will provide high value to users while minimizing development and maintenance costs.

Well, there's a bit more to it actually. Read more into these steps in the well-developed user, content and context attributes Lou wants you to consider in the process of developing IA. It's like a checklist of questions you should pose to a project team when planning and writing requirements for your project.