Cleary, Brian.A Mink, a Fink, a Skating Rink: What Is a Noun? Lerner, 2000. For readers in grades 2 to 4. Part of a series called Words Are Categorical, including To Root, to Toot, to Parachute: What is a Verb? and Hairy, Scary, Ordinary: What is an Adjective?
Fowler, H. W.Ed. R. W. Burchfield.The New Fowler's Modern English Usage. Oxford University Press, 1996. Indispensable primary source on grammar, pronunciation, and spelling; includes comparisons between British and American English.