The Essential Guide to Alien Species is a reference book released by Del Rey in 2001, written by Ann Margaret Lewis, and illustrated by R. K. Post. It covers 140 species in detail and an additional 25 in a section in the back of the book. The book comes with a handy chart with the planets and their constituent species, a pronunciation guide, and a timeline detailing events from 3,000,000 BBY to 30 ABY.

Like The New Essential Chronology and Galactic Phrase Book & Travel Guide, this book "exists" also as an in-universe publication, written by Mammon Hoole.

An astonishing testament to the power of Human imagination, the Star Wars epic has become perhaps the most captivating myth of modern times. Now comes the first detailed look at more than 150 of the most fascinating alien species that inhabit this vast galaxy. Who these creatures are, how others see them, how they evolved, where they can be found...it's all here—thoroughly researched, brilliantly illustrated, packed with surprising facts, and featuring an exclusive pronunciation guide to the names of the key Star Wars species.

Discover the only alien species that can make the savage Tusken Raiders run for cover

Learn why the Hutts think they are gods—and why their infants spend the first fifty years in the dark

Compare the tracking skills of the Ewok hunters, the legendary Wookiees, and the secretive Shistavanen wolfmen

Explore the powerful bond between the amphibious Gungan and the fiercely loyal kaadu

From Jawas, Slashrats, and Space Slugs, to Weequay, Dugs, and Gank Killers—get the lowdown on the intriguing denizens in the Star Wars universe