Merriam-Webster's Dictionary of English Usage

“This is the ultimate guide for the perplexed. You’ve heard different rulings on the split infinitive. Who(m!) to believe? MWDEU traces the history of every rule it describes, telling you which classic grammarians uphold the rule and which oppose it. It also goes to the written evidence itself, and then makes its own ruling with eminent good sense. Is this usage rare and widely condemned? Don’t do it. Is that so-called ‘rule’ a recent invention that has never been truly followed? It’ll tell you that too, in entertaining (even surprisingly cheeky) mini-essays on every controversy you can think of.” Read more...

Grammar Books That Prove What They Preach

Lane Greene, Journalist