William Blake The Marriage of Heaven and Hell, Fitzwilliam Museum, Trumpington Street, Cambridge (01223 332900) to 30 Nov. Free
William Blake, the 18th-century painter, poet, political radical and visionary, first glimpsed heaven, aged 8, in a tree filled with angels on the common at Peckham Rye. He never looked back.

The visions that haunted the rest of his life were also at the centre of his work: in his poems and paintings and in the privately printed books in which he combined the two. It was a calling that kept him apart from other men, a little too close to madness for most folk's liking, but which led to one of the most extraordinary bodies of work in the history of English art.

Many of Blake's best paintings were done as illustrations to his illuminated books but original copies are rare and fragile and tend to be kept in glass cases, open at a single page, making it impossible to view the whole except in facsimile reproduction. Until now.

The Fitzwilliam Museum in Cambridge, owners of one of the finest Blake collections in the country, have just unveiled The Marriage of Heaven and Hell in its unbound entirety. It will be re-bound and returned to the dark in due course, but until the end of November it offers a unique chance to see all the words and pictures together.

Even seen in all its splendour, The Marriage remains one of Blake's most puzzling texts; a dense combination of poetry, prose and proverbs with pictures of swirling figures, flames and old men crawling. The real puzzle, however, is that Blake's art was obscure and impenetrable one minute, wise and insightful the next.

The Fizwilliam's exhibition, which also includes a range of other books and drawings, is a must for Blake enthusiasts.

EYE ON THE NEW Gerhard Richter, one of Germany's most successful living artists, is the subject of a 30-year retrospective at Edinburgh's Fruitmarket Gallery. The focus is his Multiples - a complete set of the prints, photographs, sculptures and paintings that he has editioned since 1965.

At 45 Market Street, Edinburgh (0131-225 2383) to 27 Sept