This puts me in the minority of reviewers here, but I didn't like the book. High-Rise requires a inordinate amount of suspension of belief. They was so much suspension that I didn't think there was anything left that was tangible to reality.
I do agree that if given the chance, there are people, like Wilder, who will succumb to their lowest, primal instincts. I also agree that in group settings, people become more dangerous and instinctual. However, I just cannot accept how everything was plotted out, mainly the turning point from normal to heightened hostility. The ending didn't surprise as much, but the execution of the turning I thought was poor.
I think Ballard was too excited by the idea of apartment tenets raiding each others' apartments in violent clans and taking everyone back to the stone age that he rushed everything to get there.
I did think the last page was intriguing, and it made me wonder if similar events were happening on the outsider OR if the apartment mayhem would eventually surround to other areas and consume.