This book, published to coincide with the theatrical release of George Lucas's "Star Wars" prequel on May 19, 1999, considers the scientific plausibility of the Star Wars phenomenon now depicted in four motion pictures: "Episode I: The Phantom Menace" (1999); "Episode IV: A New Hope" (1977); "Episode V: "The Empire Strikes Back" (1980); and "Episode VI: Return of the Jedi" (1983). The author holds a BS in astrophysics, did graduate work in astronomy, and taught astronomy at Michigan State University and Cornell University before working in the Astronaut Training Division at NASA's Johnson Space Center in Houston. Cavelos admits to an early interest in science fiction that led to sustained interest with space exploration and in alien life forms. These preceded an eight-year career in publishing and a senior editorship in science fiction/fantasy at Dell Publishing Company. Cavelos herself has written "The Shadow Within," Book 5 of the "Babylon 5" novels (1997) and "The Science of the X-Files" (1998).

With this unique background, Cavelos sets out to scientifically explore the Star Wars universe. In addition to the four theatrical motion pictures and the "Special Editions," she also refers to the "Star Wars Holiday Special" (1978), a two-hour made for television video), and Stephen J Sansweet's "Star Wars Encyclopedia" (1998). She draws upon a variety of scientific disciplines and at least 47 named experts from various fields in her analysis. Unfortunately, Cavelos does not provide any direct citations to publications, correspondence, or her oral interviews with the "experts," so that even direct quotations lack any references, precluding the verification of the quoted statements. This is particularly distressing should the reader wish to investigate a specific topic in greater depth. However, the reader can enjoy a narrative uncluttered with in-notes, footnotes, or endnotes. The scientists whom she quotes span an extraordinary range of disciplines. The book has five topical chapters and sidebar comments but, unfortunately, no illustrations or diagrams.

In "Planetary Environments" (Chapter 1) there are four sidebar essays and seven sections, among these topics such as "You Can't Have an Empire without Real Estate" and "The Bright Center of the Universe." The subjects covered include planet formation, star systems, tidal forces, biochemical factors needed for life, high-energy particles, Tatooine's desert environment, and Owen and Beru's moisture farm. We are informed that "life is common, that there are two billion earth-like planets in our galaxy, and that water is the best medium for carbon-based chemical reactions. One essay, "Twin Suns" evaluates and challenges the probability that Tatooine would have two suns, while another considers Endor's moon and potential radiation problems.

Cavelos's "Aliens" (Chapter 2) has eight sections and three essays. She writes, "the universe according to Lucas is filled with life" - Jawas, Hutts, Ewoks, Gungans, Wookiees, etc. The major topics include "How Alien are Alien?" (bacteria, mutations, and the pentadactyl -- five digit -- advantage), "Do Your Ears Hang Low?" (eye mobility, heat dissipation, and flexible necks), and "The Dawn of Wookiee" (an assessment of bipedalism and quadrupedalism) and the perplexing question why Wookiees lived originally in trees. In "Slugfest" she characterises Jabba and the predator Space Slug (Hutts are also slugs), in addition to "When Teddy Bears have their Picnic" (the physiology and behaviour of koalas, chimpanzees, and Ewoks), and "Did You Leave Your Headlights On?" (evaluating Jawas and Sand People, optics, photoreceptors, and bioluminescence). Notably, it would be highly unlikely for aliens from different planets to survive in a single environment, such as the Mos Eisley cantina. Being a slug, Jabba supposedly travels on a coating of secreted slime using undulating motions. Yet, in the enhanced 1997 version of Episode IV, Jabba moves with ease in the xerophytic environment of Tatooine but he should be desiccating.

"Droids" (Chapter 3) has eight topics and two essays. Among these are "Wheels or Legs?" (relationships of body shape, coordination, and locomotion), and "I, Droid" (neural networks, rule-based versus case-based systems of intelligence, and memory wipes). Other sections, such as "Do You Hear What I Hear"(communicating with intelligence, will, understanding, emotions, and pronunciation and accents), "Do Droids Dream of Electric Sheep?" (the brain in decision making and personality development), and "I'm Okay, You're an Overweight Glob of Grease" (neurochemistry, emotions, instinct, logic, and holography), "I Whine, Therefore I Am" (conveying emotions -- with Furbys and Tamagotchi entering into this discussion). "The Six-Million Dollar Sith" enters the world of prosthetic limbs, amputations, industrial accidents, airway-lung damage in burn cases, and voice augmentation devices (such as the one used by the actor Christopher Reeve). One section is devoted to the topic "Why Han and Threepio Will Never be Friends" (age, sex, culture, education, and situations that affect learning and emotion are some of the factors considered). Cavelos also comments on the unresolved proposition: "can and should we create a robot that feels pride, fear, frustration, and affection?" Hence, could or should there be a world inhabited by C-3POs or R2-D2s? Another essay assesses the efficacy of "All-Terrain Armored Transports" (ATATs).

In " Spaceships and Weapons" (Chapter 4), with ten topics and three essays, Cavelos considers the velocity of light, laws and principles of Newton and Einstein, fuel requirements (chemical fuels vs. nuclear fusion), matter and antimatter, hyperspace and wormholes (the latter, incidentally, suggested initially by Albert Einstein). Topics elaborated in sections entitled "When 'Faster than A Speeding Bullet' Just Isn't Fast Enough," "When You Came in Here, Didn't You have a Plan for Getting Out?," and "The Music of the Spheres," include superstring and particle theories, and a multidimensional universe (with up to ten dimensions). In "Which Way is Up?" and "Which Way is Down?" she reveals principles about real and artificial gravity, and antigravity craft (such as Jabba's Sail Barge). Cavelos presents us with a half dozen explanations of "Han's Boast" (e.g., the error that he "made the Kessell Run in less than 12 parsecs") - parsecs are measurement of distance, in this instance, 228 billion miles -- rather than time. "When in Doubt, Blast!" and "Lightning Bolt on a Stick" assess weaponry, laser technology, the inability to focus six laser beams (so much for the Death Star's weapon), lasers that stun, plasma weapons, and the control of light saber beam length

The final and longest part, "The Force" (Chapter 5) has ten sections and seven essays, and documents elements (the Greek earth, fire, air, water, and ether -- the latter equivalent to force?), concepts of zero-point energy, neutrinos, precognition, tachyons, and five types of forces (strong nuclear, weak nuclear, electromagnetic, and gravity, plus "The Force"). Telekinesis, the EPR paradox, control and consciousness, hypnotherapy, parapsychology, telepathic communication, clairvoyance, remote viewing, and psychokensis are among the other major topics considered. "May the Force Be with You," "Where Jedi Fear to Tread," "Zen and the Art of Nerf Herding," "Peeping Jedi," and "A Jedi Pick-me-up" are some of the section titles. "Could a Scientist be a Jedi?" (a qualified "yes"), "Are You Online with the Force"(mind control and levitation), and "Invaders from the Fourth Dimension" (superstring theory) are impressive essays.

The narrative sections and sidebar essays in this book range widely through many scientific concepts, science fiction topics, and Star Wars characters. In her independent examination of the use and misuse of science, Cavelos creates a compelling narrative and transports readers from science fiction to science fact and probability. For example, she documents the interrelationships of the principles of quantum physics and the propulsion and armaments of the Millennium Falcon. There is a great deal of scientific material presented in a lucid, non-trivialised, well-written style. A reader does not need a scientific background to understand the aspects of science she presents in spite of the diverse information drawn from astronomy, biology, computer science, cosmology, ecology, geology, physics, psychology, and zoology, among other disciplines. Cavelos demonstrates how George Lucas and his colleagues incorporate current science fact into science fiction and -- more importantly -- how science is catching up with Lucas. In sum, this delightful volume is fun to read and presents important aspects of various scientific disciplines. It is appropriate reading for a variety of audiences, but particularly seasoned and young scientists, and science fiction aficionados.