Recommendations on Non-GMAT Guides to Learn Grammar

I plan on taking the GMAT soon, and sentence correction has so far given me a bit of trouble. I have skimmed through the usual GMAT verbal guides, and I have noticed that they try to "reverse-engineer" the SC section, i.e. prior released GMAT questions inform their rules; for example, a guide would say something like, "Question 29 on GMATPrep allows for some degree of pronoun ambiguity, so pronoun ambiguity isn't sufficient to eliminate an answer choice." In essence, in several guides, the concepts discussed focus only on those that have been covered in prior GMAT questions. While these guides are helpful, I would want to learn the actual logic behind these grammar rules in a broader, non-GMAT setting. The scope of GMAT SC isn't limited to just material covered in the past- it covers a very broad spectrum of effective verbal communication. A question on the actual GMAT might cover a grammar rule that has never been tested before. Therefore, I am seeking recommendations on grammar books whose conceptual explanations are not "biased" by standardized tests, and I feel that learning from this will help me on my GMAT. I realize that there might be better places to ask for grammar book recommendations, but I am seeking help from people who have used non-GMAT books to study for the GMAT, and I am sure there are a few.