Mary Czerwinsky and Victor Kaptelinin have edited a book about future desktop metaphors.
More you can find out via

• Amazon.com (link from Richard Boardman)
• The page about the book at MIT press

Here is what they say themselves, copy-pasted from the first chapter:

The objective of this book is to present and discuss new approaches to designing next-generation digital work environments. Currently the most pervasive computer systems, such as Microsoft Windows and Mac OS, are based on the desktop metaphor. For many users and designers, these are the only digital work environments they have ever known. It is all too easy to assume that the desktop metaphor will always determine our experience of computer systems. The present book challenges this assumption. Its point of departure is an understanding that desktop systems as we know them may well represent a temporary—if hugely successful—phase in the development of interactive environments. Future systems may further develop, modify, or even abandon the metaphor.

I can only add: for me, the Semantic Desktop is only the first step needed towards cyberspace! Lets make new metaphors! (as blogged before one two three times)

If you like Semantic Desktop, think about buying this book. For me, the reasons are threefold:

• First, I chatted with Mary Czerwinsky over a cup of coffe in Kaiserslautern, back in January 2005 and she said she is preparing a book on future desktop metaphors - aha! Nifty I am, I added a todo to my organizer to remind me a year later if the book is there - it was not, but I moved the todo to remind me in another year...
• Second, I recently tried to find out more about Richard Boardman, who is my secret hero for completing a PhD (btw: how could anyone ever ever finish a PhD?), and he blogged about the book, because he is in it. Reading his blog, it hit me: that is the book.
• Third, because my clever Diploma Thesis student Danish Nadeem has found the book and recommended it to me. That was another reminder saying: you should buy this book NOW

So, I had a todo-item in my organizer saying "buy the future desktop metaphors book from Mary", which I today, after 17 months, can close. Three cheers to Mary Czerwinsky and Victor Kaptelinin for making it! Thanks for Danish to remind me.