Recommended Reading Order
While some readers have shared that it's possible to read the books out of order, I'd still strongly suggest going Monster > Siren > Parasite. The first novel does the heavy lifting of setting the tone and background for the series and makes the concept, characters, and universe much more convenient to digest.
If you want a quick sampler, you can jump directly to Smolder. It's shorter than the Vertex books but still sheds a little light on the corporation's nature, enough, hopefully, to pique your interest in the rest of the universe. Do note that it's a holiday story, with a lighter, more humorous tone than the Vertex series books.
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