I laughed with Aiken Drum, cried with Elizabeth Orme, sympathized with Bryan Grenfell, and trembled at Felice Landry's rage. Our heroes embark on escaping the servitude of the alien, psychically-powered Tanu. The plot thickens, the action escalates, the characters evolve-- some even die, sometimes fulfilled, sometimes not. This is space opera at its finest.
Even secondary characters-- certain alien Tanu that actually sympathize with enslaved human-- are touching. You understand something of their motivations, their soul.
All while reading in disbelief, wondering how May writes such effortless, vivid scenes. Her creativity is unmatched-- the world she sees must have color, sound, texture all magnified to the umpteenth degree.
Yes, you might need a dictionary to read some of her books. But what joy, to learn such new, colorful words, and savor how she uses them!
This series is rich in content, incredibly so. It's delightfully complex, with hundreds of plot threads and references woven together into a compelling tapestry. It's emotionally powerful without being sappy. It's rich in philosophical, historical, cultural, and etymological allusions, and it's meticulously researched. You'll need to flex your brain muscles, but you'll be happy to do it. You'll laugh, you'll cry, you'll stretch your vocabulary.
The four Pliocene books are, in my opinion, May's best. The others in the Galactic Milieu series run a close second. Her other stuff is so-so, readable but not exceptional. I was struck initially by the story, and also by the quality of the writing. It's so different, and much better, than anything else I've read in the genre, and manages to largely avoid the usual time travel anachronistic and self-referential cliches.
I've recently finished reading the whole thing (including the other Milieu books) yet again, and I'm still amazed and moved by the experience, from the initial familiarity with the need of the misfits to leave, to the ultimate understanding of Atoning Unifex. Tremendous stuff.