Reviewers praised the description of Gracehope and main characters, as well as the performances of Coleen Marlo and David Ackroyd who voiced Thea and Peter in a subsequent audiobook publication of First Light.

She also explains that her research of mitochondrial DNA relates to the ability of mutations to benefit the human body, which could cause their extremely good vision and hearing.

To convince the rest of the colony, Peter and Thea plan to use a piece of mythology, that a dog with four white paws would be supposedly born when it was time to leave.

Thea decides to proceed without using the dog and tries to convince the colony at a reenactment of the Settler's escape to Greenland with several allies who know of Rowen's actions.

That, coupled with the fact that Peter is an eye adept, the first in a hundred years, convinces the colony to listen to Thea instead of Rowen.

Katie Haegele from the Philadelphia Inquirer also listed the novel as a "slow-to-unfold mystery combining elements of science and history with an appealing note of fantasy".

[4] Connie Tyrrell Burns from School Library Journal found the novel to be "an exciting, engaging mix of science fiction, mystery, and adventure".

Kirkus Reviews found that "With the impending threat of global warning as an ominous backdrop, teens from very different worlds find they have much in common".

Burns felt that First Light is a "great discussion starter of issues ranging from global warming to shunning and building a new society".

[6] Publishers Weekly said, "It is a testament to the storytelling that the existence of this parallel world and the convergence of Peter and Thea's stories, told in separate chapters, are both credible and absorbing.

[4] Vicky Smith from Horn Book Magazine found the two main characters well written and the city of Gracehope well structured.

Hubert criticized the slow beginning and flaws in the mythology and structure of the underground world, but still felt that "the icy setting and global-warming theme are well realized".

Kathy Miller from School Library Journal praised the two readers for their performance which "engages listeners, and they are both adept at creating a different voice for each character and moving seamlessly between them".