Bruce Tognazzini

It's hard to read through a book on the principles of magic without glancing at the cover periodically to make sure it isn't a book on software design.

If it ain't broke real bad, don't fix it.

Constrain the user's expectations to match the abilities of the software.

When the users cannot be completely isolated from a reality of the operating system, we must fully expose the users to that reality, no matter how painful a prospect that may appear.

Never present a power-user option in such a way that normal users must learn all about it in order to know they don't need to use it.

If a feature is good enough to be included in a new release, it is good enough to be fully integrated, not left to grow on the side of the old one like a goiter.

If we are to isolate and insulate our users from the reality of the system software, we must take great pains to ensure that isolation is complete.

The Creeping Learning Curve: Every change made to the software, even those "trivial" little changes assimilated day by day by the design team, will be re-experienced, all at once, by each user upon first running the new revision. If your team of spends 6 months, and adds 1 feature each day, your users are going to be hit with 6 months worth of changes, all 180 of them, in the first 6 minutes.