All three novellas are very good.

“The Four Thousand, the Eight Hundred” explores a civil war on an asteroid colony generations after the colony was founded.

“Dispersion” is about a planet inhabited by six groups that are cyclically intangible and invisible to each other. Then a new disease spreads among all six groups and the race is on to find the cause and a cure. Very good descriptions of how the six groups cyclically are able to interact.

“Phoresis” tells of two tidally locked planets where one is slowly becoming uninhabitable. Interesting and courageous folks explore possible solutions and work to make them happen.