John Armstrong was born in 1893 in Hastings. He studied at St. John’s College, Oxford, 1912-13, and then at St. John’s Wood School of Art 1913-14. During the war he served in the Royal Field Artillery 1914-19, before briefly returning to St. John’s Wood School. He began his professional career as a theatre designer in London, gaining important patrons including Lillian and Samuel Courtauld, who commissioned Armstrong to decorate a room in their Portman Square home. His first solo exhibition was at the Leicester Galleries in 1928. In 1933 he joined Unit One alongside Ben Nicholson, Paul Nash, Edward Burra, Henry Moore, Edward Wadsworth, John Bigge and Barbara Hepworth, with whom he exhibited at the Unit One exhibition. From the early 1930s onwards his work became Surrealist in style – uncanny, romantically dream-like and heavily imbued with symbolism. Armstrong died in 1973. His work is held in numerous international public collections including the Tate, the Imperial War Museum, and the National Galleries of Scotland.

Upon the break-up of his second marriage to Veronica in 1955, Armstrong left Lamorna in Cornwall and returned to London. The majority of his output during this phase of his life was still-life paintings, frequently featuring vases, fruit, and vegetables. An increased tendency towards abstraction and an exploration of the formal qualities and interrelationships of elements within the paintings began to surface, last evident in Armstrong's work from the 1930s. Writing in an article entitled 'The Round and the Flat' in 1958 for The Studio, Armstrong discussed the formal foundations of painting:

'The representation of objects seen or imagined is necessary to me, not for the objects themselves but for certain of their material qualities or for their power of emotional suggestion. The material qualities that attract me to particular objects are those of convexity, concavity and flatness. Anything through which these can be clearly expressed and contrasted will serve to try to resolve the conflict between pattern and tactile form which is to me one of the most absorbing of the conflicts of art.'

The move towards abstraction visible in the still-lives from the late 1950s developed by the start of the 1960s into a series of purely abstract paintings, including 'Megalopolis', a veritable masterwork from this era, and 'Phantom', 1959; Government Art Collection, amongst others. In 1972, Armstrong described his geometric work thus: 'I found I could do abstract painting only if I used exact mathematical forms - triangles or squares, rectangles. I got very interested in them - one leads on to another.' The paintings from the mid-1960s are devoid of all suggestion towards figuration, a logical progression from the preceding works such as 'Megalopolis' which still contains suggestions of recognisable subject matter. Although the primary focus of 'Megalopolis' is on a geometric abstraction - on colour, form, interrelations, the paint surface - the patterning is highly suggestive of either a series of upright human figures or the built-up skyline of a city, both intimated at by the title, 'Megalopolis'.

In 'Megalopolis' a profusion of irregular vertical rectangular structures extend across the surface, interweaving and overlapping with one another. Various apertures, abstracted doors and windows, break up the solidity of the structures so that other rectangles appear through and atop one another: all sense of logical layers is thwarted as rectangles enclose, intersect, form and disrupt other rectangles. Perspectival understanding seems continually just beyond grasp - hints of receding streets leading to open doors or urban vistas are confused by areas of total abstracted flat patterning. A muted colour palette, restricted to warm autumnal colours of yellows, purples, creams, browns, greens and oranges, keeps form and structure as the focal essence of 'Megalopolis'. As with all of Armstrong's oeuvre, abstract or otherwise, the surface of the painting is integral to the work. In 'Megalopolis', although painted in oil, the paint has a beautiful tactile dry, chalky quality, frequently seen in Armstrong's oils from 1958 onwards. The weave of the canvas becomes part of the texture of the surface, showing through with a grainy quality, augmenting the pattern of interconnecting structures. Amongst Armstrong's most successful abstract work, and on a significantly larger scale than most of his output throughout his career, 'Megalopolis' sits at a powerfully effective juncture between tactile patterning of colour and form, and elusive, surreal suggestions of a metropolitan cityscape.