http://juicy.mellon.org/RIT/MellonOSProjects/TK4/

TK4 is a is a project to develop an open-source authoring system for 
media rich electronic documents. It is a continuation of work begun at 
Voyager 12 years ago.

The underlying assumptions are: a) the locus of serious intellectual 
discourse is inevitably shifting from page to screen. b) for this shift 
to occur we need among other things, tools which will enable 
non-technical people to assemble digital documents without needing to 
learn complex computer languages or to rely on programmers.

TK4 builds upon the lessons learned in TK3 to bring an easy to use 
software creation toolkit to the masses. TK4's model, like TK3, is that 
of a book, with links to many forms of annotations. (For information on 
the predecessor project, TK3, please see http://www.nightkitchen.com)

Built in Smalltalk using the Squeak VM and later the Tweak VM, TK4 
extends TK3 by being written in a late binding, runtime environment 
allowing third parties to plug into the architecture at virtually any 
level. End users will be able to extend TK4 by writing object level 
smalltalk behaviors, which while sounding daunting at first, is very 
powerful as many forms of editing can be layered onto the smalltalk 
(programming via text, via behaviors, via dragging objects)

TK4 interoperates with itself through a collection of servers which 
handle message distribution, allowing new concepts to be added into the 
system without disturbing those already in place.

One major goal of TK4 is to make sure that a user's content remain 
accessible for many years, if not decades to come. To afford this, TK4 
will use a distributed XML format which will be human readable as long 
as the media it is stored on is accessible. Should a particular title 
need features beyond those provided by TK4, such as performance or 
databasing, nothing prevents those systems from being plugged in on a 
per book or per distribution basis.

TK4 also extends on TK3 in terms if resizable type, resizable books 
while still allowing the Author to control final delivery settings. 
There is much more in TK4, such as time associated with the book and 
web based viewing of content.