About five years ago there was a burst of excitement about the future of the Johannesburg Gas Works, the defunct early 20th-century red brick and steel industrial cathedral just beyond 44 Stanley in Milpark. There was talk of the site being developed as a mixed-use precinct with flats, shops, a hotel, offices and parkland.Nothing came of it and that's just as well, because a new book from independent publishers Fourthwall Books, simply titled The Johannesburg Gas Works, explores the site's unique potential for what you might call urban acupuncture.It shows how the site is not just interesting for its history, but for the possibilities it presents to bring about radical change to Johannesburg's urban fabric.In its simplest (somewhat deceptive) form, the book is a beautifully produced homage. It is filled with current and historical photographs, maps and architectural drawings from company and private archives, and fascinating accounts of the life and workings of the site.These resources were uncovered by Monika Läuferts le Roux and Judith Mavunganidze of Tsica Heritage Consultants when they were commissioned to do a heritage report on the site.As they put it in the foreword, they hoped "to bring the gas works site alive for every Johannesburger who has wondered what lies beyond those brick walls on Annet Road".But Gas Works ultimately does so much more than that. Two essays that bookend the rich historical material transform it into something quite extraordinary, and take it way beyond a mere appreciation of the dilapidated beauty of the site.The first is a social, industrial and architectural history of the site by Clive Chipkin, Johannesburg's best-known architectural historian. In his typically even-handed, effortless and elegant style, Chipkin takes in the sweep of the social, economic and political history of the last century and reveals how it speaks in the design of the building.He doesn't shy away from the history of oppression and exploitation that was at the heart of Johannesburg's rapid industrialisation in the first half of the century, but through the historical richness and complexity he brings to the site, sets the stage for its transformative power.The second is an analysis of the potential of the site to bring about urban transformation by architecture lecturer, artist, commentator and designer Alexander Opper.He argues that the gas works' landmark status gives it the "perceptual pull and anchorage" to breach some of the divides inscribed on the city's fabric.If the gas works were re-imagined as a "porous public space" rather than another walled-off mall, it could "graft together the divided patchwork of multiple urban fragments surrounding it".Opper goes so far as to suggest that if Braamfontein's railway yards were reinvented as something like New York's High Line, between it and the gas works they would make it possible to safety walk or cycle all the way from, say, the University of Johannesburg to "Joubert Park and even Ellis Park and beyond".Observations like that make it possible to imagine how a few well-placed interventions have the catalytic potential to bring about real, street-level change.A well-conceived architectural pinprick could reconfigure the city, while at the same time creating new, inclusive narratives for historical sites in the way perhaps that Constitution Hill has done.Seen like that the book positively vibrates with the energy and riskiness of its conception. It makes history come alive in the most thrilling way...