National Geographic Books is getting in the digital shorts business. On March 20, the division will release the first in a line of e-book shorts, Titanic: Uncovering the Secrets of the World's Greatest Shipwreck by Mike Sweeney for $4.99. The titles in the series will range from 5,000 to 15,000 words.

National Geographic is set to publish four other e-books in spring: Mysteries of Jesus: Exploring the Miracles of Easter (also set for March 20), Rhino Wars: The Violent Underworld of Poachers and Black Market Medicine (April 17), 36 Healing Herbs: The World's Best Medicinal Plants (May 1), and Shark Attacks: Inside the Mind of the Ocean's Most Terrifying Predator (June 5). All four e-books will be $3.99. Following the spring launch, titles will be released at the rate of about one per month.