Walk into any bookshop nowadays and you will see a whole table of nature books, from explorations of remote rural places, to stories of bygone farming life through to portraits of individual species – the owl, the hare, the fox. The combination of urban blight and lockdown 'cabin fever' has led us to turn to the countryside as never before.

Back in 1967, when a Chelmsford council flat resident John Alec Baker wrote 'The Peregrine', things were very different. There was nothing at all like it – and to this day, it stands out from the crowd.

The book chronicles Baker's obsession with the peregrine falcon, the graceful predator of the skies that in his time was nearly hunted and poisoned to extinction but is now thriving. The book has no dialogue and no plot, and nothing happens but observations of peregrines through the seasons of Baker's beloved haunts – Great Baddow, West Hanningfield, the Blackwater down to Heybridge.

Two things have made the book a cult title which obsesses its readers across the world. One is Baker's ability to put us in the head of the bird as it glides, swoops, observes its prey and dives (at over 200 mph) on its victims. The other is the extraordinary poetry of his language, described as "trippy" and "Essex landscape on Acid".

All this from a shy, retiring man who worked for the Automobile Association (but didn't drive), was severely myopic, subject to depression, had no TV or phone, and rarely socialised.

Baker found freedom in his kinship with the Peregrine: "I shut my eyes and tried to cystallise my will into the light-drenched prism of the hawk's mind… I sank into the skin and blood and bones of the hawk."

J A Baker died in 1987, when Peregrines were still under threat: they had been hunted in World War II when they preyed on carrier pigeons used by the armed forces, and the widespread use of chemicals in farming after the war decimated them. But now they are thriving: more organic farming methods have helped, and Peregrines have adapted to urban landscapes, even nesting in the Jumbo water tower in Colchester.

Baker's writing is far from cute: nature is harsh and often bleak, though there are moments of comedy, like when he describes a peregrine flying low over some game birds on the ground and knocking them over like skittles just for play.

His book sits amongst the many modern successors in most bookshops, and still thrills to this day.