Within the Deep / Cassell's "Eyes and No Eyes" Series, Book VIII.

The work offers a reader-friendly natural history of sea life through a sequence of illustrated lessons covering fishes, marine mammals, and reef communities. It treats the ecology and behavior of familiar species such as herring, flatfish, seals, and sharks, explains spawning and nursery areas, describes feeding habits and dangers of the deep, and surveys coral reefs, rock-pool inhabitants, and unusual fishes. Practical human connections — fisheries, nets, and whaling — appear alongside naturalistic detail, while plates and drawings support descriptions of form and habitat. The tone is explanatory and accessible, intended to introduce young readers to marine biology and coastal ecosystems.