This is a book with which few Observer readers will disagree. It champions “social infrastructure”, meaning libraries, urban farms, playgrounds, sports grounds and all the other shared spaces that allow people to make connections, form networks and find ways to know and help one another. It doesn’t like Trump, racial segregation or climate change denial. Its theme is important and timely, but it leaves you wanting more.

Eric Klinenberg is a sociologist based at New York University, who made his name with a study of a lethal 1995 heatwave in his native Chicago. There, he discovered that the likelihood of death or illness from the heat related not only to deprivation and social position, as might be expected, but also to the physical form and condition of the neighbourhood – “bombed-out” areas, with vacant lots and ragged streets, made their residents’ chances worse. Places with similar demographics but more cohesive fabric fared better. It seems they encouraged the cooperation and support that helped people survive.

This is the territory of Jane Jacobs, whose 1961 book The Death and Life of Great American Cities praised the inherent sociability of a traditional street. In Palaces for the People Klinenberg takes these lines of inquiry further. He stresses the importance, where Jacobs didn’t, of publicly funded facilities. He makes the case that the physical spaces and conditions that make communal life require investment just as much as bridges, roads and all those other works of heavy engineering that usually go under the title of infrastructure.

And so he spends time in public libraries, seeing how people of differing ages, status and ethnicities cohabit their spaces, how conflicts are negotiated and collaborations start, and how these institutions give refuge to people who feel excluded or diminished elsewhere. He describes an initiative in Brooklyn libraries where older people can play in virtual bowling leagues as a way of getting them out of their homes and meeting people.

He talks about the importance of school gates as places where parents can get to know one another and the loss of that opportunity in schools with drive-through drop-offs. He looks at what happens in catastrophes, as when Hurricane Harvey hit Houston, and churches helped flood-hit families to save and reorganise themselves. He draws on his own experiences, when he was appointed research director to the rebuilding programme after Hurricane Sandy hit New York in 2012.

All these themes play out against a background of new forces making division, conflict and simple misery more likely – the opioid epidemic, in which Klinenberg believes isolation has played a part, and climate change. There are also the effects of the internet, although he is at pains to avoid the casual assumption that social networks automatically make people less social. He does, however, challenge Mark Zuckerberg’s bland promises to assist “meaningful communities”.

Indeed, if you made the background of the book its foreground, it would be a devastating portrayal of fragmentation, despair and disruption. But Klinenberg, an optimist, tells heartwarming stories of abandoned lots in Englewood, Chicago, that have been converted to agriculture, of “geriatric parks” in Spain, complete with age-appropriate play equipment, of measures in Singapore to help people of different generations know one another. He mentions ambitious plans by the architecture firm Big, as part of the post-Sandy response, to protect lower Manhattan from floods with barrier parks – infrastructure that would be useful and pleasurable at once.

No reasonable people could not want these things and it’s a public service to lay them out. What the book lacks is a desire to tackle the hard questions, such as: how much do things like this cost and how are they paid for? How do you sell them to public authorities and voters in today’s hostile climate? It’s notable that many of the success stories are in the authoritarian state of Singapore – how can they be transferred to western democracies?

The book would also benefit from a tougher edge when telling its feelgood stories. It would be more credible if it told more of what happened next, of what works and what doesn’t. As for Big, my knowledge of the company’s work so far suggests that it is not the go-to practice for effective and cost-effective public work. I would be fascinated to discover that it is, in fact, achieving such a thing in New York, but the evidence isn’t there.

All of which means that the stories and insights come with a certain amount of mush. The conclusion is majestically woolly: “What we need, now more than ever, is an inclusive conversation about the kinds of infrastructure – physical as well as social – that would best serve, sustain and protect us.” Try putting that on an election poster. Or a tweet.

• Palaces for the People: How to Build a More Equal and United Society by Eric Klinenberg is published by Bodley Head (£18.99). To order a copy for £16.33 go to guardianbookshop.com or call 0330 333 6846. Free UK p&p over £10, online orders only. Phone orders min p&p of £1.99