Grammar reference books
Leech: An A-Z of English Grammar and Usage (Nelson)
Murphy: English Grammar In Use (CUP)
Swan: Practical English Usage (OUP)
Swan & Walter: How English Works (OUP)
Thomson & Martinet: A Practical English Grammar (OUP)

Practice books
Allen: Living English Structure (Longman)
Bromberg & Liebb & Traiger: 504 Absolutely Essential Words (Barron’s)
Capel & Sharp: Wendy Sharp Objective Proficiency Student’s book (CUP) new
Evans: CPE Use of English (Express Publishing)
Evans: FCE Use of English 1 & 2 (Express Publishing)
Gude & Duckworth: Advanced Masterclass (OUP)
Gude & Duckworth: Proficiency Masterclass (OUP)
Hall: Objective Proficiency Workbook (CUP)
Harrison: Proficiency Testbuilder 1&2 (Macmillan-Heinmann)
Harrison & Kerr: CAE Practice Tests (OUP) new
Jones: Progress to Proficiency (CUP)
May: The Complete Proficiency Practice Tests (Heinemann)
Obee & Evans: Entry Tests & Practise Tests for the Revised CPE (Express Publishing)
O’Connell: Focus on Proficiency (Longman)
Skipper: Advanced Grammar & Vocabulary (Express Publishing)
Thomson & Martinet: Exercises 1 & 2 (OUP)
Triggs: CAE Practice Tests (Heinemann)
Turton: ABC of Common Grammatical Errors (Macmillan-Heinemann)
Vince: Advanced Language Practice (Macmillan-Heinemann)
Vince: First Certificate Language Practice (Macmillan-Heinemann)
Walton: Advanced English CAE Grammar Practice (Longman)
Wellman: The Heinemann English Wordbuilder (Heinemann)