Mary Hynes-Berry (Children's Literature)
In this book, Willems uses features of the exuberant style that is his signature to create an easy-read book. Though they are little more than stick figures, the expressions on the faces of Willem’s creatures give them plenty of personality. The text is spare--the first of each double spread asks “Cat the Cat, who is that?” On the next spread, Cat the Cat scoots from one page to the next identifying her friends such as Mouse the Mouse, Duck the Duck, and Fish the Fish. But even Cat is stymied when she comes to a two-eyed, four-armed, three-legged creature playing with blocks. However, the alien’s greeting “Blarggie, Blarggie” is enough to convince Cat the Cat to use this as her name. Emergent readers will get plenty of reinforcement from the highly repetitive text and the picture clues. The success of Willem’s “Elephant and Piggie” series suggests that they also will be quite happy to go back again and again to practice their emerging skills with this book. 2010, Balzer & Bray/Harper Collins, $12.99. Ages 4 to 6.

Kirkus (Kirkus Reviews, March 1, 2010 (Vol. 78, No. 5))
Mo is back, and Cat the Cat has arrived. The spare, animation-inspired aesthetic, bright colors and speech-bubble text that characterize many of Willem's works are present in this new picture-book series, which could also serve well as beginning reader fare. In this inaugural title, the sweet, eponymous character encounters friends at every page turn, whom she readily identifies as Mouse the Mouse, Duck the Duck, Fish the Fish and so on. But when she discovers a seven-limbed monster playing with building blocks, she can only respond "EEP!" to the text's oft-repeated prompt, "Cat the Cat, who is that?" Like Leonardo the Terrible Monster (2005) before him, this monster happily turns out to be a good friend, and Cat the Cat joins him in joyfully shouting, "Blarggie! Blarggie!" and crashing through the block tower. Move over Pigeon, Piggie and Gerald, there's a new cat in town, and she's most welcome. 2010, Balzer + Bray/HarperCollins, 32p, $10.99. Category: Picture book/early reader. Ages 2 to 7. © 2010 Kirkus Reviews/VNU eMedia, Inc. All rights reserved.

Publishers Weekly (Publishers Weekly)
In Cat the Cat's friendly world, names are an uncomplicated affair, most of the time. This early reader pictures Cat, an irrepressible kitty in a purple dress, skipping and cartwheeling to greet pals like Mouse the Mouse and Fish the Fish. All is well until Cat meets a chartreuse creature with eyestalks, a blue tongue, four arms, and three legs. She skids to a halt and her tail electrifies. The individual, unrecognizable but clearly amiable, stops stacking blocks to say, “Blarggie! Blarggie!” This time Cat's initial response to the repeated question, “Cat the Cat, who is that\n?” is “I have no\n idea,” but Cat finally decides this might be “a new friend!” and responds with a bouncy “Blarggie!” of her own. Willems provides just enough humor and surprise to entertain youngest audiences and subtly suggests some future reading: Duck the Duck cradles a Pigeon doll, and in a second book being released simultaneously—Let's Say Hi to Friends Who Fly!\n—another character rides a Pigeon playground toy. Cat could become another favorite; her personality sparkles in expansive gestures and gleeful interactions. Up to age 5. (Feb.)\n"

Elizabeth Bush (The Bulletin of the Center for Children's Books, May 2010 (Vol. 63, No. 9))
Into his teeming menagerie that already encompasses Knuffle Bunny, Pigeon, Elephant and Piggy, and their legion of sidekicks, Willems now introduces Cat the Cat and her buddies. The debut title, Cat the Cat, functions pretty narrowly as a get-acquainted session, as the purple-frocked feline meeting each new critter by answering the narrator’s query of “Cat the Cat, who is that?” with a name patterned after her own—Mouse the Mouse, Duck the Duck, Fish the Fish. Audience prediction breaks down, though, at the encounter with a multi-limbed, stalk-eyed alien who responds, “Blurggie! Blurggie!” Sorry, kiddies, but it’s not Blurggie the Blurggie, but simply and rather disappointingly “a NEW friend!” The clever quotient rises a level in the second title, Let’s Say Hi. Again, Willems supplies a pattern: “‘Can you fly, Bee the Bee?’ ‘Watch me!’” A bird and bat nimbly follow suit, but Rhino the Rhino seems less promising until he takes off in a plane. Vocabulary is consistently easier in Let’s Say Hi, with monosyllables and sight words all around, and none of Cat the Cat’s adult-dependent twists like “pleasure” and “blurggie” to confound neophytes. Both, however, deliver the perennial amusement of Willems’ heavily outlined, friendly, slightly naďve animals and—for joy!—hidden pigeons. Emergent readers and their phonics teachers will applaud this new launch Review Code: Ad -- Additional book of acceptable quality for collections needing more material in the area. (c) Copyright 2006, The Board of Trustees of the University of Illinois. 2010, Balzer + Bray/HarperCollins, 24p., $10.99. Ages 2-5 yrs.