Grammar/Punctuation/Spelling

Eats, Shoots and Leaves, Lynne Truss (Profile)
The Grouchy Grammarian: A How-Not-To Guide to the 47 Most Common Mistakes in English Made By Journalists, Broadcasters and Others Who Should Know Better, Thomas Parrish (Wiley)
Penguin Dictionary of English Grammar (Penguin)
Penguin Guide to Punctuation (Penguin)
Mind the Stop: A Brief Guide to Punctuation With a Note on Proof Correction, GV Carey (Penguin)
Cassell’s Dictionary of English Grammar, James Aitchison (Cassell)
New Oxford Dictionary of Spelling (OUP) A companion volume to Hart’s Rules (see style/usage)