Michael Swan. Practical English Usage. Oxford University Press, 2005. ISBN 9780194420983.
This standard reference work on British English has recently been updated to cover practically any language and usage question you can think of. All topics are listed alphabetically and explained in simple language.
John Peck and Martin Coyle. The Student’s Guide to Writing: Grammar, Punctuation and Spelling. Macmillan, 1999.
The book is divided into “Writing Correctly”, “Writing Confidently” and “Writing with Style”, and includes the basic rules. It is not culture bound, but is a guide to the British English we use in South Africa.
Jane E. Aaron. The Little, Brown Compact Handbook.7th edition.Pearson Longman. ISBN 13: 9780205651634; ISBN 10: 0205651631.
This is one of the best American guides on English. It is a comprehensive and very well set out guide to written English, and includes guidance on research and writing academic papers, as well as guides on the main academic reference systems (Chicago, MLA, APA, etc). Indexing, cross-referencing and examples are excellent. Just remember that in certain respects such as punctuation American usage differs from the British usage that is standard in South Africa.
Pieter du Toit, Marie Heese and Margaret Orr. Practical Guide to Reading, Thinking and Writing Skills. Southern, 1995.
A book specially written for South African students.
Jennifer H. Addleson and Digby J Ricci. Writing Wrongs: A Communication Skills Handbook. Academica, 1989.
Another South African book, with practical application for students.
L.G. Alexander Right Word, Wrong Word: Words and Structures Confused and Misused by Learners of English. Longman.
This is like a dictionary but at the same time it is more than that. It has exercises covering a whole spectrum of interesting areas, such as work and jobs; asking, requesting and commanding; comparatives and superlatives; and counting and measuring.
Betty Kirkpatrick. Better English, Geddes & Grosset. David Dale House, New Lanark. ML119DJ, Scotland.
It has topics from the sentence to the paragraph to handling spoken English. Every subject area is explained very simply for easy accessibility, which enables any student of English to understand and appreciate the content. A teacher can also use it as reference material for any level.
Bill Bryson. Mother Tongue. Penguin.
A really good read, packed with information, and attractive for the general inquirer.
David Crystal. The Cambridge Encyclopedia of the English Language. 2nd edition, 2003. Cambridge University Press.
This answers a great many general questions in an accessible style.