Six years ago the British Library put on a much appreciated exhibition of maps of London curated by the head of its map collections, Peter Barber. At the same time, it published a book by Peter Whitfield that, though ostensibly on the same subject, was in no sense a catalogue of the exhibition. Running these two things together was confusing.

Now at last comes this huge and beautiful book, produced with assistance from the London Topographical Society, which reflects the care and scholarship that went into the original exhibition. There are many things in it I have been delighted to find again, including some plans for what never was. Before