I know of no such work; and I suspect that if there were such a work it would be of very little value to you.
Complex sentences arise because their authors are trying to express complex thoughts, and in the end what drives the shape of the sentence is not the grammar and syntax of English (or any other language) but the relationships between the various 'propositions' which go into what the authors are trying to express.
Think of it this way ... A writer is like a carpenter, who draws on two resources provided by her language:
a lexicon or vocabulary, which is a vast (and constantly growing) warehouse of materials for building things: bricks, concrete, timbers, planks, sheets of plywood, pipes, wires, cables, shingles, plaster, tiles, paint, nails, screws, bolts, straps, brackets, and all the other materials which go into building a house
a grammar, which is a toolkit, a collection of hammers, saws, shears, chisels, screwdrivers, wrenches, planes, measures, squares, levels, and all the other tools used to bring the materials into usable shape and join them into usable constructions
(Note that this description slides over the fact that a lot of the pieces available in the warehouse are prefabricated constructions which the carpenter slots into her own construction without troubling herself with their internal structure: junction boxes, garbage disposals, light fixtures, and the like. This is the subject-matter of a fairly new linguistic discipline, Construction Grammar, to which you may find an introduction here; but for our present purposes it’s a side-issue.)
These resources are described (in greater or lesser detail) in works like Merriam-Webster’s Collegiate Dictionary, the Oxford English Dictionary, Aarts’ Oxford Modern English Grammar and the Cambridge Grammar of the English Language, and (more or less) helpful guides to their use like those by Fowler, Strunk & White, Swan and Grammar Girl. Both writers and readers have to master the use and significance of these resources for any communication at all to take place.
BUT ...
None of these resources is of any use whatever without a third piece: a blueprint. Something to say and a scheme for saying it.
No amount of carpentry knowledge will provide a blueprint. It is true, of course, that any moderately skilled carpenter can build you a respectable birdhouse or bookshelf; but that is because she already has a pretty clear idea of what a birdhouse or bookshelf ought to look like and how it functions. And insofar as she is applying that idea to her work, she is not functioning as a carpenter but as an expert in a very different discipline: as an architect, a designer of blueprints.
For an architect, the materials and tools (and prefab constructions) are merely constraints on what she can accomplish. She is primarily concerned with function: with creating interpenetrating spaces and surfaces and installations which accomplish some purpose: a residence, a place of worship, a factory, a school, a theatre, a railroad station, an office complex. Each of those different purposes has different requirements and poses different problems; and it is those requirements which drive her decision to put this piece here and that piece there, to build using this material rather than that material, to employ this technique rather than that. In consequence, understanding “the steps and thought processes behind” her decisions cannot be directed to the carpentry, the lexicon and grammar; it has to be directed to the architecture, the function.
So linguistic commentary on a text is not going to tell you much of any value—that’s just carpentry. To understand a legal or philosophical or critical or biological text you have to understand law or philosophy or criticism or biology; and commentary must in the first instance address function to be of any value. Closer attention to the carpentry will only blind you to the function. It is to the function that your attention should be directed.
You will protest, naturally, that it is impossible to grasp a complex argument fully if you cannot grasp all the details on which it is founded, and your unfamiliarity with English—with the carpentry—makes it impossible to grasp the details. This is, I think, an error. You can, in fact, grasp the argument without worrying too much about the details. Don’t try to get the entire argument on your first reading of a text; instead, move through it swiftly and find out where the argument is going. Once you know where the author is ending up, you can backtrack and fill in the local details, because your knowledge of the destination will tell you what each component has to mean for the argument to make sense.
And observe: this approach has two advantages.
First, it puts your primary focus on what both you and the author are primarily concerned with, which is what she is saying. Invest your energy where it will yield the highest return.
Second, when you do this an amazing and apparently paradoxical result will emerge: you will learn the carpentry without putting any particular effort into it. You will in fact be learning English the same way small children do: by attending to the meaning rather than the expression.
Michael Polanyi (Tacit Knowing) writes of this:
Tools are akin to the particulars of a comprehensive entity, for an object is a tool by virtue of the fact that we rely on it for accomplishing something to which we are attending when using the tool. In this case we can, admittedly, identify the thing on which we rely, even though mostly we do not quite know how we actually use it. But it is still true that we cannot direct our attention to a tool as a mere object, while relying on it as the tool of a skilful performance. You must keep your eye on the ball, and if you look at your bat instead, you lose the stroke. A skilful performance is paralyzed by attending focally to its particulars, whether these are the dexterous movements of our body or the tools which we employ.
The skilful use of a tool actually identifies it to an important extent with our own body. The rower pulling an oar feels its blade tearing the water; when using a paper-knife we feel its edge cutting the pages. The actual impact of the tool on our palm and fingers is unspecifiable in the same sense in which the muscular acts composing a skilful performance are unspecifiable; we are aware of them in terms of the action our tool performs on its object, that is, within the comprehensive entity into which we integrate the effective use of a tool. The same is true of a probe used for exploring a cavity or a stick by which a blind man feels his way. The impact made by a probe or a stick on our fingers is felt at the tip of the probe or stick, where it hits an object outside, and in this sense the probe or stick is integrated to our fingers that grasp it.
A feature of great importance enters here in the way the assimilation of an instrument to our body is achieved gradually by learning to use the instrument intelligently. When first groping our way blindfold with a stick, we feel it jerking against our hand. But as we learn to understand these jerks in terms of the impacts of the stick against outer objects, we begin to feel the end of the stick knocking at these objects. Thus the jerks against our hand, when integrated to our purpose, undergo (along with a change in quality) a transposition in space. We see here that when a particular is integrated into a comprehensive entity it may acquire a meaning which is sensed at some distance from the original position of the particular, at which it had been previously experienced in itself, meaninglessly. Other examples of such shifts, directed likewise away from our body, will be met in the use of language and the act of visual perception.
We can pass from probes to language by thinking of pointers. We rely on our awareness of a pointer in order to attend on what it points at, and this is its meaning. Seen in itself, as a mere object, the pointer is meaningless. [...]
When we identify the elements of speech to which we are not attending at the time of our utterance, and switch our attention to them, our utterance becomes meaningless. Repeat the word table, table, table, twenty times over, attending carefully to the sound of the movement of your lips and tongue, and the meaning of the word will become remote, and finally dissolve altogether. That is often expressed by saying that words used meaningfully are transparent and that, when we concentrate on a word as a sound, it becomes opaque. The transparent word is like a telescope through which we see its meaning—while, when rendered opaque, the word ceases to show us things beyond itself and blocks our sight by its own meaningless body. To make explicit our tacit knowledge of a spoken word is to destroy the comprehensive entity, the sign-gestalt, to which the word contributed.
