Colophon

The animals on the cover of Continuous Delivery in Java are lanternfish, a family of fish known as Myctophidae. Lanternfish get their name from their natural bioluminescence, which causes them to glow with blue, green, or yellow light. This light is produced by organs known as photophores, which are arranged along the body and head of the fish. It is theorized that bioluminescence plays a role in communication between lanternfish.

Small and slender, Lanternfish are covered in silvery scales. They live deep in the ocean, diving deeper by day and rising at night. They are a major food source for marine predators, such as whales, dolphins, tuna, and sharks, making them an important link in the oceanic food chain.

Lanternfish are extremely numerous, and are estimated to make up 65% of all deep sea fish biomass. They account for much of the deep sea scattering layer, a phenomenon where ships’ sonar is scattered off the swim bladders found in deep sea fish, causing false depth readings. Although common in the wild, there is very little commercial fishing of lanternfish.

Many of the animals on O’Reilly covers are endangered; all of them are important to the world. To learn more about how you can help, go to animals.oreilly.com.

The cover image is from Lydekker’s Royal Natural History. The cover fonts are URW Typewriter and Guardian Sans. The text font is Adobe Minion Pro; the heading font is Adobe Myriad Condensed; and the code font is Dalton Maag’s Ubuntu Mono.