Twenty-five years ago, when I left Zimbabwe to study in Canada, my father gave me copies of Roget's Thesaurus and Fowler's Modern English Usage. He urged me to keep these books "at my elbow" and promised that, if I did, they would forever be good and useful companions on my journey as a writer. He was right. To this day, the two volumes lie within arm's reach of my desk and I find myself perusing them from time to time, even when I don't have anything in particular to look up. A dictionary and thesaurus are integrated directly into the operating system of my computer and my word processor truculently insists on correcting my grammar by placing squiggly green lines under my prose. However, neither of these digital systems, useful as they are, can match the delight I experience from Fowler's, which is wonderfully clever, opinionated, irreverent, and entertaining.
Break open Fowler's to any page and you will be treated to entries like this one on the use of the word instance.
Or this one on the distinction between principle and principal, which I reproduce here in its entirety.
I love these books, particularly Fowler's. I hope that you come to love them, too.