The Isokon building, Lawn Road Flats, in Belsize Park on Hampstead's lower slopes, is a remarkable building. The first modernist building in Britain to use reinforced concrete and architecture, its construction demanded new building techniques. But the building was as remarkable for those who took up residence there as for the application of revolutionary building techniques. There were 32 Flats in all, and they became a haunt of some of the most prominent Soviet agents working against Britain in the 1930s and 40s. A number of British artists were also drawn to the Flats, among them the sculptor and painter Henry Moore; the novelist Nicholas Monsarrat; and the crime writer Agatha Christie, who wrote her only spy novel N or M? in the Flats. The Isokon building boasted its own restaurant and dining club, where many of the Flats' most famous residents rubbed shoulders with some of the most dangerous communist spies ever to operate in Britain. Agatha Christie often said that she invented her characters from what she observed going on around her. With the Kuczynskis - probably the most successful family of spies in the history of espionage - in residence, she would have had plenty of material.

Sheffield has been synonymous with steelmaking since the eighteenth century and with cutlery for centuries before that. But while it has an extraordinary variety of industrial buildings connected to its metal trades, there is another side to what is England's least known big city. Set amidst magnificent scenery, it has some surprising survivals of its earlier history, as well as handsome public, commercial and religious buildings designed by its Victorian local architects. The leafy western suburbs that rise towards the Peak District were described by Sir John Betjeman as the finest in England. The 1950s and 60s saw the city famed for its innovative public housing, university buildings and churches. After the decline of its manufacturing sector in the 1980s, major new venues for sport and entertainment, the prize-winning Peace Gardens and exciting new buildings such as the Millennium Galleries, Winter Garden and Persistence Works are visible signs of a renaissance in the city's fortunes. This is the first comprehensive architectural guide to Sheffield. It describes the buildings of the city centre and those of the inner suburbs within a two mile radius of it. It also covers the lower Don valley, still the heart of Sheffield's steel industry, the outer suburbs to the west where those who made their fortunes from it lived in splendour and there are excursions to some outstanding buildings on the outskirts. Major buildings including the Town Hall, the two Cathedrals and the Winter Garden are given more detailed treatment, as are the two Universities. The central areas are the subject of walks, those further out have suggested tours by car. Illustrated throughout in colour with specially commissioned photographs and with these images augmented by historic maps, paintings and drawings, Sheffield will enable residents to look at familiar buildings in a fresh light and encourage visitors to discover for themselves the city's enticing contrasts of industrial heritage and natural beauty.