ALA Booklist (Fri Jan 01 00:00:00 CST 2010)

Though written in a modern idiom ("Yuck,' I thought. Who wants to be a merchant?'"), D'Agnese's introduction to medieval Europe's greatest mathematician offers both a coherent biographical account un, with some invented details, from very sketchy historical records d the clearest explanation to date for younger readers of the numerical sequence that is found throughout nature and still bears his name. O'Brien's illustrations place the prosperously dressed, woolly headed savant in his native Pisa and other settings, contemplating flowers, seashells, and the so-called arabic numerals (which he promoted vigorously and rightly ascribes to India), as well as presenting a visual solution to his most famous mathematical word problem. Closing with a page of relevant activities for young naturalists, this picture book makes an excellent alternative to Joy N. Hulme's colorful but flawed Wild Fibonacci: Nature's Secret Code Revealed, illustrated by Carol Schwartz (2005).

Kirkus Reviews

"You can call me Blockhead, everyone else does." So Leonardo Fibonacci declares in first-person voice in the opening of this picture-book biography. Who was he? Fascinated with numbers as a child, Leonardo grew from a daydreaming boy in medieval Italy to become one of the greatest European mathematicians of the Middle Ages. He found something to count everywhere, but his father wanted him to be a merchant and took him to North Africa to do his accounts. Leonardo learned fractions from the Egyptians, geometry in Greece and Hindu-Arabic numerals from India. He wrote a book that posed his mystifying, multiplying rabbit question. The lively text includes touches of humor; Emperor Frederick called him "one smart cookie." O'Brien's signature illustrations textured with thin lines re-create a medieval setting. The last page lists things to find in the pictures, like a three-leafed clover and spirals, as well as activities that reinforce his concepts. Few people will know this man's name, but the book will be a boon to math teachers, homeschoolers and others piqued by the title. (Picture book/biography. 6-10)

Publishers Weekly (Fri Oct 06 00:00:00 CDT 2023)

Math lover or not, readers should succumb to the charms of this highly entertaining biography of medieval mathematician Leonardo Fibonacci. “You can call me Blockhead. Everyone else does,” opens the lighthearted narrative. As an adult, he works out a math problem that involves reproducing rabbits and discovers a pattern that repeats itself in nature, which becomes the sequence of numbers that now bears his name. Hence, his obsession is vindicated: “All my life people had called me Blockhead because I daydreamed about numbers. But how could that be bad? Mother Nature loved numbers too!” D'Agnese's colloquial tone (King Frederick II calls Fibonacci a “smart cookie”) lures readers into the story and even invites them to ferret out patterns in the illustrations. Atop dappled backgrounds, O'Brien's delicate swirls and hatch marks echo the mathematical patterns—another graceful connection between math and the real world in which children live. Ages 6–9. <EMPHASIS TYPE=""ITALIC"">(Apr.)

School Library Journal (Mon Mar 01 00:00:00 CST 2010)

Gr 2-5 Leonardo does his math problems so quickly that he has plenty of time to look out the window and count other things in nature. His teacher, however, chastises him for daydreaming and the other students call him a "blockhead." Only his father's advisor, Alfredo, understands that Leonardo has a fascination with numbers, a love that will eventually help him become the "greatest Western mathematician in the Middle Ages." As an adult, Fibonacci imagines the figure of Alfredo continuing to help him refine his theories. Although the book is presented as a biography, the author states that "little is known about the life ofLeonardo Fibonacci" and no sources are listed. Entertaining in the vein of the "You Wouldn't Want to Be" series, this lighthearted introduction to Fibonacci's ideas will inspire young math lovers and perhaps point them toward more scholarly explorations. The illustrations have a medieval look to them but without any stiffness or fussiness. They include many touches of humor and are well suited to the story. Painted with a broad pointillist style detailed with pen and ink, the pictures incorporate many visual references to Fibonacci's work, such as swirling features suggestive of the spiral, a key element in the mathematician's theories of nature. Lucinda Snyder Whitehurst, St. Christopher's School, Richmond, VA