Todd Morning (Booklist, Feb. 1, 2005 (Vol. 101, No. 11))
When twins Marty and Grace O'Hara discover that their adventurous parents have gone missing, they leave their Swiss boarding school and join their mysterious uncle, Travis Wolfe, on his island in Washington State. They soon learn that their uncle is one of the world's foremost authorities on cryptids (think Bigfoot and the Loch Ness Monster). Wolfe is scheduled to look for dinosaurs in the African jungle, and he plans to leave Marty and Grace in Europe before the expedition starts. Things go awry, however, when an accident plunges Marty and Grace into the middle of the Congolese jungle. Soon the henchmen of the evil Noah Blackwood are pursuing the twins. The action is nonstop in this well-paced jungle adventure, and Smith adds a deeper layer in scenes of Marty and Grace discovering truths about their complicated family relationships. Several loose ends suggest more cryptid-recovery expeditions to come. Category: Books for Middle Readers--Fiction. 2005, Hyperion, $15.99. Gr. 5-8.

Tim Davis (Children's Literature)
As this exciting adventure opens, Marty and Grace O’Hara, 13-year-old twins in a private school in Switzerland, receive the terrible news that their parents are presumed to have died in a helicopter crash in the Amazon. Apparently orphaned, Marty and Grace are sent to Cryptos Island in Washington’s Puget Sound to live with their uncle, Dr. Travis Wolfe. In short order, though, the cryptozoologist Wolfe--a scientist who seeks evidence of legendary wildlife, i.e. Sasquatch, the Loch Ness monster, and even dinosaurs surviving in the 21st century--and his new associate, Dr. Laurel Lee, must leave on an urgent trip. Wolfe and Lee have heard about a fertile dinosaur egg from the nest of the legendary mokčlč-mbembč in the Congo, so they must fly to Africa to recover the precious evidence, and, of course, Marty and Grace go too. In the fast-paced quest which follows, Marty and Grace are accidentally jettisoned from the airplane and drop by parachute into the deadly African jungle. Making matters worse, dangerous villains are looking for the precious egg and the young adventurers. The twins, however, are resourceful heroes, and the jungle and villains are no match for the O’Hara team. In the end, though, the discoveries Marty and Grace make about themselves, their family, and the most persistent villain, Noah Blackwood, will challenge them far beyond their wildest expectations. Even the most reluctant readers should thoroughly enjoy this tale of science, fantasy, and adolescent resourcefulness. 2005, Hyperion Books, $15.99. Ages 10 to 16.

Kirkus (Kirkus Reviews, December 15, 2004 (Vol. 72, No. 24))
When Uncle Wolfe takes them on a dinosaur hunt, orphaned twins Grace and Marty find themselves in a B-movie with email. When the twins' explorer parents vanish in the Amazon (to be found in the next book?), mischief-maker Marty and genius scaredy-cat Grace go to live on Uncle Wolfe's private island. Wolfe hunts cryptids: mythical creatures such as Yetis, Kraken, and Chupacabras. Though he doesn't intend to bring the children on his dinosaur hunt in the Congo, they arrive anyway, after falling from his airplane into the darkest jungle, accompanied only by a teacup poodle, a chimpanzee named Bo, and a high-end Gizmo complete with videoconferencing. There the children must reunite with their uncle, find the mythic dinosaur MokFlF-mbembF, and avoid the minions of evil Dr. Blackwood. Luckily there are friendly Pygmies to help. And what is the deep, dark secret that has given Grace nightmares all her life-and what does it have to do with Dr. Blackwood? Enjoyably rollicking adventures are appropriately cheesy; the stereotypes, though equally fitting, are a bit much. 2005, Hyperion, 352p, $15.99. Category: Fiction. Ages 10 to 13. © 2004 Kirkus Reviews/VNU eMedia, Inc. All rights reserved.

Publishers Weekly (Publishers Weekly)
Readers expecting Jurassic Park–\nstyle adventures may be frustrated by the small role exotic creatures play in Smith's (Zach's Lie\n) farfetched story. As the novel opens, 13-year-old twins Grace and Marty meet the uncle they never knew when their parents go down in a plane crash. Travis Wolfe, their uncle, is a reclusive "cryptozoologist" who lives on the private island Cryptos and researches animals "whose existence has not yet been proven scientifically." Wolfe's archenemy, Noah Blackwood, a conservationist well-known for his animal theme parks (called "Noah's Ark") and television appearances, is secretly a ruthless collector of rare species, which he then "harvests." Wolfe and Blackwood clash when an "alleged dinosaur egg" enters the picture; matters worsen when Grace and Marty are accidentally airdropped into the Congo, and Blackwood turns out to be hunting not just the egg but Grace herself. Logic takes a back seat when a convoluted family tree begins to emerge (though the author plants a clue at the start, when he says of the twins, "but you wouldn't know it if you saw them together")—it turns out Grace is not only Wolfe's daughter but Blackwood's granddaughter (Wolfe married Blackwood's daughter), while Marty is indeed Wolfe's nephew. An abrupt action sequence on the last few pages leaves many questions unanswered and plot lines dangling. This unsatisfying journey is less about cryptids than it is about soap opera–esque family intrigue. Ages 10-up. (Feb.)\n"

Krista Hutley (The Bulletin of the Center for Children's Books, January 2005 (Vol. 58, No. 5))
After their photojournalist parents disappear, thirteen-year-old twins Marty and Grace leave boarding school to stay with their heretofore-unknown uncle Wolfe on his private island. Wolfe owns a lucrative electronics company, but this is only to finance his more pressing interests--finding and protecting "cryptids," a term for animals not proven scientifically to exist. Once the twins arrive, Wolfe finds he must make an emergency trip to the Congo, where Noah Blackwood, an old enemy whose fame hides his unethical exploitation of animals, has discovered the secret habitat. En route back to boarding school, Marty and Grace snag a parachuted ride down with the supply drop over the Congo; there, Grace realizes that everything is familiar, leading her to wonder if she's been there before, and if so, when? Smith layers action adventure and psychological drama as the characters converge in the Congo and discover secrets about themselves along the way. Marty and Grace are deliberately idealized children with prodigious talents, yet they are human enough that readers will allow these occasional forays into unlikelihood, since they further the plot. Their relationship has everything a brother/sister duo needs to succeed: their bickering and annoyance is tempered by love and affection, and their willingness to support each other, even when it turns out they are not twins, is believably sweet. Smith doesn't muddy the waters with nuanced adults, either; good guys and bad guys are straightforward and don't change sides, allowing readers to relax and enjoy the ride. The detailed, exotic locale and the novelty of hunting for scientifically unsubstantiated animals will be more than enough to snare young readers. (Reviewed from galleys) Review Code: R -- Recommended. (c) Copyright 2005, The Board of Trustees of the University of Illinois. 2005, Hyperion, 352p, $15.99. Grades 5-9.

Kathleen Roseboom (The Lorgnette - Heart of Texas Reviews (Vol. 18, No. 1))
The O’Hara twins are as different as night and day. Grace is quiet, studious, and has terrible nightmares. Marty is adventurous, daring, and full of pranks and “fantastic” ideas. When their parents are missing after a plane crash, their Uncle Wolfe sends for them, and they arrive on an island off the coast of Washington State and discover unique animals and unusual people with “unusual skills.” This book is adventure packed with non-stop action--granted some of it is a bit far-fetched and outrageous--but it is a mover and a shaker. It should keep the mind active, the legs moving, and the mind challenged...Cryptic Hunter? Cryptozoology? The study of animals that are believed to exist but cannot be proven to exist scientifically. The rarest animals on earth examples--Bigfoot, Loch Ness monster. Roland Smith has other books that are for reluctant readers, and this one is sure to reel in several and open the door to the discovery of imagination and basically becoming the character of Marty (or Grace) and finding themselves having “green eggs and mamba” for breakfast! Fiction, Highly Recommended. Grades 5-10. 2005, Hyperion Books, 348p., $15.99. Ages 10 to 16.

Michael Levy (VOYA, October 2004 (Vol. 27, No. 4))
This fast-moving adventure novel reads like something from the 1950s-positioned halfway between Tom Swift Jr. and a Heinlein juvenile book. The protagonists are twins who seem nothing alike. Marty is a smart aleck, a fine athlete, and a wonderful cook. Grace, a genius, is afraid of her own shadow and has disturbing, possibly psychic dreams. When their parents are lost in a plane wreck in the Amazon, the twins are taken out of their boarding school in Switzerland and shipped off to Cryptos Island in Puget Sound, the home of their mysterious uncle, Dr. Wolfe. He is a super-scientist who specializes in the study of cryptids, creatures that cannot be proven to exist, like the yeti or the Loch Ness monster. Soon Wolfe and his loyal team are on their way to the Congo, racing to find the last living Mokčlč-mbembč, a smaller cousin of the brontosaurus, which has been rumored to have survived in Africa for centuries. When their chief competitor, the fabulously wealthy and definitely evil scientist and television personality, Dr. Blackwood, sends a team of thugs to capture the dinosaur for his own nefarious purposes, things turn desperate. Grace and Marty manage to fall out of an airplane and find themselves lost in the heart of the Congo with dangerous animals all around and Blackwood's thugs closing in. The unlikely plot is all great fun, although Mokčlč-mbembč, when it finally appears, is something of a disappointment. All in all it is an exciting but not particularly challenging read. VOYA CODES: 3Q 4P M J (Readable without serious defects; Broad general YA appeal; Middle School, defined as grades 6 to 8; Junior High, defined as grades 7 to 9). 2004, Hyperion, 348p., $15.99. Ages 11 to 15.