I got the book "Web Form Desing: Filling in the blanks" by Luke Wroblewski a few weeks after it was published and read it several times since, but recently I got to an understanding that this book is much more then a design / UI best practices book.
In its essence this is a book about reducing the entropy as a way to convey proper information. Let me explain this point.
A form is a visual element that usually distracts the user from his main purpose, and thus needs to perform some sort of a context switch in the user's mind, and as with every context switch, it gets more and more costly when the new process needs more information and time to process. Now, a form has a lot of building blocks, part are explicit (like the fields) and part are implicit (like label positioning) and every little thing that is reflected on the design of the form, effects the "price" a user needs to pay in order to process it.
In my mind, Luke had found the right way to minimize a form's noise thus achieving a reduction in the form's entropy, and as any information theorist will tell you, less entropy means more information. Basically, since the brain is the decoder of the visual information, what Luke had discovered is how to properly code the form's information in a way that would result in an optimal signal to noise ratio in the brain.
Moreover, this book combines this information theory concept of getting the information out of the signal while reducing the noise with a zen like approach that states that everything matters, and in order to get to perfection, you can never say "it doesn't matter" on anything, because anything matters. If you think that it doesn't matter, then search deeper for the meaning of the differences between the different choises you confront.
I guess that Luke didn't intend to write a book about information theory and zen, but as I see it, this book is the projection of the combination of these two things on the web forms design axis.
This is an excellent book, for anyone, and especially for those that have a hard time living with mediocor solution when a perfect solution is right around the corner.
Update - this is what Luke wrote me as a response to this entry:
Thanks Yoav, appreciate the review and the lens you took on it. In essence, you hit the nail on the head: minimize the pain of the context shift of the form by not ignoring any details so that you can get people to their real goals :)