Here is a pdf version of "Morphic: The Self User Interface Framework", the original paper describing the Self version of Morphic (also available in compressed postscript).
There is also a chapter from the nublue book on the original Squeak version of Morphic which is somewhat out of date; a lot of layout related and event handling has changed since it was written.
Dan Ingalls worked with John Maloney to get Morphic running on Squeak's BitBlt-based graphics kernel. Dan went on to implement the compatibility package that allowed all the MVC programming tools to run in Morphic, as well as such morphs as polygons, curves, transformationMorphs (using WarpBlt) and the full run-around text package.