Compact Oxford English Dictionary (OUP). The full 13 volumes photographically reduced to two, in slip case with a magnifying glass.

Shorter Oxford English Dictionary (OUP). Two volumes of the essence of the OED.

Concise Oxford English Dictionary (OUP). A further distillation to just one volume.

Oxford English Reference Dictionary (OUP). A mix of dictionary and encyclopaedia.

Illustrated Oxford Dictionary (Dorling Kindersley)

Collins English Dictionary (Collins)

Chambers 21^st Century Dictionary (Chambers)

Concise Oxford Dictionary of Politics (OUP)

Oxford Dictionary of Idioms (OUP)

Oxford Dictionary of Foreign Words and Phrases (OUP)

Oxford Concise Science Dictionary (OUP)

New Penguin Dictionary of Abbreviations (Penguin)

Penguin Dictionary of English Idioms (Penguin)

Roget’s Thesaurus (Longman’s). Quirky, but by far the best

Oxford Thesaurus (OUP)