Wittgenstein, in a letter to von Ficker, has this to say about his Tractatus Logico-Philosophicus:

“The book’s point is an ethical one. I once meant to include in the preface a sentence which is not in fact there now but which I will write out for you here. … What I meant to write, then, was this: My work consists of two parts, the one presented here plus all that I have not written. And it is precisely this second part that is the important one. My book draws limits to the sphere of the ethical from the inside as it were, and I am convinced that this is the only rigorous way of drawing those limits.”

This 128 page bookwork is based on a facsimile of the manuscript for this text. Each page has been reproduced with the ‘text’ removed, leaving only corrections and notations. The book also exists in a trade edition. Go here for more on Michael Maranda.