Excellent program - well-designed, lean and fast, with a deceptively simple interface and many, many nice details and options. HBN 2 was a smart, easy-to-use notebook, HBN 3 was a powerful but somewhat quirky outliner, but 3.5 combines the best of both versions and adds so many new features and interface enhancements that 4.0 would be a more appropriate version number.
As a notebook program, HBN competes with dozens of others, but what makes it unique is that instead of trying to fill a niche in this crowded market, it integrates the functionality of outliners, notepads, text processors and file databases into one single, elegant application and leaves it up to you how you want to use it. You can have different notebooks for specific tasks, or use one single notebook for everything related to the project you're working on: Make a to-do list, jot down some ideas, collect information from web sites, use HBN's powerful search features to find keywords and their context, add links to files on your hard drive, start writing the sections of your essay or book, re-arrange them, split them, merge them, and if you're done, select the final chapters and export them to a single Word or RTF file. The possibilities are endless. Chances are that HBN will become the most used application on your computer.
The interface is very flexible and customizable and makes it easy to navigate through huge collections of notes. I take one star off in the ease-of-use category because the shortcuts are not very intuitive and some features aren't self-explanatory. Other than that, it's first-class software. And a steal for $20.