Travels of Category Theory for the Working Mathematician

For a special issue on Math+Travel MAA Focus sought photographs from around the world featuring the iconic yellow cover of Saunders Mac Lane’s Categories for the Working Mathematician.

The yellow Springer book Categories for the Working Mathematician lying on a polished wooden choir stall, the long Gothic nave of Worcester Cathedral receding behind it with patterned tiled floor and pointed arches — Categories for the Working Mathematician on the choir stalls of Worcester Cathedral. This photograph became the cover of MAA Focus, Vol. 45, No. 1 (February/March 2025).

The Worcester Cathedral photograph became the cover of the February/March 2025 issue of MAA Focus, (Vol. 45, No. 1). Inside, a feature titled World Traveler: Categories for the Working Mathematician (pp. 26–27) gathers photographs of the same book from mathematicians around the globe, from the source of the Nile in Uganda to the Taj Mahal, Easter Island and Sydney. The contribution there from Iceland is a photograph at the Hoffellsjökull glacier.

The yellow book on a rounded boulder above a misty meltwater lagoon, a broad grey glacier tongue descending between dark ridges at Hoffellsjökull — The book at the Hoffellsjökull glacier in southeast Iceland. A photograph here appears in the World Traveler feature inside the same issue of MAA Focus.

I took a lot of other photos, seen in the gallery. In particular early mathematics from the town I grew up in.

The yellow book propped against a weathered stone tomb slab carved with rows of incised Latin capitals, set into a Gothic stone recess with a stained-glass roundel above — The book leaning on the medieval tomb slab of Walcher of Malvern, whose Latin epitaph names him a geometer and reckoner.