thoughts on editing thesis for writing sample??

[/sigh/twombly]

I am submitting a chapter of my thesis for my writing sample. The writing sample is supposed to read as a full text but the page limit means I'll only be selecting one chapter. This means my literature review and the set up of my general argument/project will be cut out. Currently, I'm editing to try to include the most essential aspects of my introduction into the chapter that I am submitting. Is this the best way to do this? Or should I just include the title of the thesis and the title of the chapter and assume that they will understand that I've cut that out (I've written about my thesis in my statement of purpose). 

How have others gone about submitting an excerpt of a thesis? 

[renea]

My chair advised me that if I submitted a portion of my thesis as a writing sample, that it should be annotated at the beginning with an explanation of what the sample is and why you are showing that part. Why not write a short paragraph stating: this writing sample is a portion of my thesis. Due to length requirements, I have chosen this sample to demonstate....xyz... 

This sort of framing will not only give the committee a preview and summary (let's face it most people skim the writing sample), but it will mean they'll have no doubt about what the sample is or why it feels disconnected/incomplete, ect.