To escape war and ecological disasters on Earth in the 2060's, a group of colonists attempt to forge a new life on a distant earth-like planet they name Pax (Latin for "peace"). They find the world is rich in flora and fauna, and appears to be ideally suited for establishing a new colony. But they soon notice that some of the plant life is sentient, and are manipulating them to further their own ends.

The colonists find an abandoned alien city made of glass and relocate their colony there. But they discover that the city is controlled by an intelligent bamboo-like plant they later call Stevland.^[a] It attempts to domesticate them in order to flourish and expand, and the humans realize that to survive, they need to share the city with it. Over time, the colonists learn to converse with Stevland using signs, and an uneasy, but mutually beneficial alliance is formed.

During one of the colonist's expeditions further inland, they meet the city's creators, the Glassmakers. The arthropod-like Glassmakers were themselves colonists and coexisted with Stevland, but they abandoned their home and became nomadic.^[b] Disease and illness decimated them and their social structures collapsed. The encounter with the Glassmakers is not friendly and leads to an attack on the city. With Stevland's assistance, the Glassmakers are repelled, and the humans, a few Glassmakers willing to coexist with them, and Stevland, form an alliance of peaceful coexistence.

In the mid-1990s Burke wrote an essay entitled "When Plants Kill".^[10] She had noticed that one of her house plants had killed another plant, and decided to undertake some research into plant behavior. She discovered that plants fight for light and nutrients, and will manipulate and even kill each other to get what they want.^[11] This formed the basis of the essay, which was published as "The Photosynthetic War" in 1997 in a science fiction magazine, Terra Incognita.^[12] In 1996 Burke participated in a Clarion Workshop, and the instructor gave the attendees a writing prompt about a wall that materializes between two warring armies. Burke considered the possibility of a planet with plants at war with each other and human colonists coming between them.^[13] This resulted in a short story "Adaptation", which she published in 1999 in LC-39, a science fiction magazine.^[14] Burke later expanded "Adaptation" into Semiosis, with the short story becoming the first chapter.^[11]

Burke finished writing Semiosis in 2004, but she was unable to find a publisher. In an attempt to generate interest in the universe she had created, Burke wrote two short stories, "Spiders" and "Cinderella Faraway".^[15][16] "Spiders" was published in the March 2008 issue of Asimov's Science Fiction, and was later reprinted in 2009 in Year's Best SF 14.^[17] The success of "Spiders" attracted the attention of several publishers, but it was not until 2016 that a deal with Tor Books was signed. Semiosis was finally published by Tor in 2018.^[18]

In a review at Tor.com, Liz Bourke described Semiosis as "a quiet, measured sort of science fiction".^[19] She said the book's central theme is about power and its use and abuse, with a "deep vein of kindness" that probes the "weaknesses and flaws of all sentient being". Bourke praised the author's "excellent grasp of voice and characterisation", despite Stevland coming across as "a little too human for an alien plant".^[19] She called the book "a very strong debut, and well worth checking out", but felt it could have been even "stronger" had not all the central characters been "cisgender straight [people]".^[19] Bourke opined that being a story about a "future attempted-utopian society", the absence of "queer people rather strains at my disbelief".^[19]

A review in Kirkus Reviews described Burke's worldbuilding in Semiosis as "astonishing", with "magnificently alien" flora and fauna, and a "richly detailed" human society.^[20] But it felt that the novel's periodic jump to the next generation makes it feel like a collection of short stories in a shared universe. The book "feel[s] rushed", plot threads "end abruptly", and "genuinely engrossing characters" remain underdeveloped.^[20] The review called Semiosis "[a]n outstanding science-fiction novel hobbled by its rushed story structure."^[20] Craig Clark also felt that Semiosis comes across as "linked short stories".^[21] Reviewing the book in Booklist, he wrote that the "multigenerational" structure of the book leads to a large cast of characters that can be "overwhelming", but praised the author's worldbuilding and the way she integrates colonization with botany, mutualism and predation.^[21] Overall, Clark called the novel "a thought-provoking look into the politics of survival."^[21]

Laci Gerhart wrote in a review of Semiosis in the journal Nature Plants that biologists may find that Pax's ecology and the depiction of its sentient plants "leaves something to be desired".^[22] The planet's fauna and flora are largely named after Earth species, which she felt lacks imagination and makes their added abilities compared to their Earth counterparts "feel less realistic". What also weakens its realism is that the indigenous sentient species "feel very human in their thoughts and behaviour".^[22] Gerhart complained about how unscientific the human scientists are. They "leap to incredible conclusions, [using] single observations and extremely limited information [as] irrefutable evidence".^[22] She acknowledged the fine line a science fiction author has to walk to appease both lay- and scientific-audiences, and concluded: "Despite these drawbacks, a plant biologist can enjoy Semiosis, particularly if one is capable of suspending disbelief on developmental capabilities in plants."^[22]

According to the review aggregator Book Marks, Semiosis received "positive" reviews, based on 7 reviews.^[23]

• Burke, Sue (2018). Semiosis (e-book ed.). New York City: Tor Books. ISBN 978-0-7653-9137-7.

• Semiosis homepage
• Semiosis title listing at the Internet Speculative Fiction Database
• Semiosis at Macmillan Publishers