The Stones of Venice has been described as the greatest guidebook ever written. Read by all who went there and thousands who did not, it opened Victorian eyes to the glories of a city even then under threat, and transformed the study and practice of architecture for ever.

It took Ruskin almost half a million words to launch his devastating attack on the Renaissance - 'the school which has conducted men's inventive and constructional faculties from the Grand Canal to Gower Street' and to explain how to s