Soignies is too small to have generated a literature of its own, but the broader context — Wallonia, Belgian history, and the Romanesque tradition — is well served in print.
La Belgique désespérément by Philippe Destatte is a sharp and honest account of the fractures in Belgian identity — linguistic, economic, political — that shape the country Wallonia is part of. Reading it helps explain why a town like Soignies, clearly Francophone and quietly industrial, feels so different from Flanders, even though they share a flag.
The Stones of Venice by John Ruskin is not about Belgium, but Ruskin's analysis of Romanesque architecture — its weight, its honesty, its rejection of ornament for its own sake — is the best preparation for standing inside the collegiate church at Soignies. His descriptions of round arches and thick pillars as expressions of a particular moral order apply directly to what you will see here.
A Tall Man in a Low Land by Harry Pearce is a gently comic travel account of Belgium written by an Englishman who genuinely loves the country. It captures the flatness, the beer, the untranslatable Belgian-ness of provincial towns — the kind of place Soignies is — with affection and accuracy. Light, readable, and the best introduction to Belgium for the resistant traveller.