But when Russia seized control of Crimea, Yevgeny Komarovsky sent this blunt message to the Russian people: We Ukrainians are a nation of our own.
"Don't impose peace on us," Komarovsky told his fans in Russia, many of whom used his books to raise their children, in a video that received nearly 1.2 million views on YouTube.
The appeal for an independent and united Ukraine by the Russian-speaking Komarovsky underscored Ukraine's distinct national identity, and belied Russian President Vladimir Putin's claim that Ukraine is part of the Russian family. In fact, Russia's invasion which Putin justifies by saying he needs to protect Russian speakers has fueled a surge of patriotism among a great many Ukrainians, whatever their language.
These feelings of unity are underpinned by a sense of fragility stemming from being a country that has for centuries been dominated by great empires to the east and west. And from folklore to ancestral traditions, Ukraine has shown itself to possess a distinct identity.
The Ukrainian national consciousness is steeped in love of one's land and the quest for survival. The challenge simply to stay whole is as acute as ever today after Russia annexed Ukraine's strategic Crimean Peninsula, stoking fears that the Kremlin is planning to invade more Russian-speaking eastern territories.
Ukraine, a land the size of France with a population of 46 million, has historically been a massive prize in the heart of Europe. The site of the ancient Slavic state, the Kievan Rus, it was the regional cradle of Orthodox Christianity. Over centuries, parts of Ukraine have belonged to Poland, the Austro-Hungarian Empire, Russia and the Soviet Union.
Ukraine is also a land steeped in 20th century tragedy conflict so traumatic that one historian has called Ukraine "Bloodland." The litany of calamities include the Bolshevik revolution and ensuing civil war that brought Ukraine into the Soviet Union; a devastating famine engineered by Soviet dictator Josef Stalin that killed millions of Ukrainians; Stalin's purges that targeted Ukraine's intellectual elite; invasion by Hitler and the murder of more than 1 million of Ukrainian Jews in the Holocaust.
Ukraine became independent in the 1991 collapse of the Soviet Union. It has since struggled to define its relationship to the world as well its ideology, shifting between aspirations to be a Western state that belongs in the European Union, or a post-Soviet republic that tilts toward Russia.
Ethnic, cultural, linguistic and religious similarities between Ukrainians and Russians as well as centuries of shared history have prompted Russian President Vladimir Putin to claim that the two nations are in fact one.
But to most Ukrainians, as well as scholars and historians, that is simply not true.
Komarovsky, who writes best-selling books on pediatrics that fight Soviet-era stereotypes such as a purported need to overfeed and overclothe children, said Putin in fact woke some Ukrainians up to the reality of who they are as a people.
"Nobody has done as much for the country's unity as Vladimir Vladimirovich Putin," said Komarovsky.
In the Russia-friendly eastern city of Donetsk, sales clerk Tetyana Ryabchenko, 58, said she was deeply hurt by Russia. "A lot of Ukrainians have changed their attitude toward Russia," Ryabchenko said. "One should look at the Russians' deeds, not words. And the deeds are horrible."
Pollsters support the view that Russia's invasion has fostered Ukrainian unity and identity.
Mykhailo Mishchenko of the Razumkov Center in Kiev said that Russia's takeover of Crimea and the threat of further incursion have fueled patriotism throughout the country.
"Views have changed, pro-Ukrainian sentiment has risen," Mishchenko said. "In this conflict between Ukraine and Russia, the predominant position is in support of Ukraine. Negative views toward the actions of the Russian leadership are clearly pronounced."
Ukrainians are also largely united by a strong independence streak that makes them suspicious of authoritarian rulers especially rulers from afar.
"It's a freedom-loving, rebellious spirit that will always remind its leaders that they are temporary and if we want to, we will oust them," said Volodymyr Yermolenko, who teaches philosophy at the Kyiv Mohyla Academy in the Ukrainian capital.
Folklore may be one indication of the differences between traditional Russian and Ukrainian mindsets.
In a popular Russian folk tale, a childless old couple transforms a dough-boy into their son. When the creature called Kolobok disobeys his parents and runs away, he gets eaten by a fox. In a similar Ukrainian tale, Ivasyk Telesyk, a boy who materialized from a piece of wood, is also separated from his parents through a twist of fate, but manages to escape an evil snake and return home.
"Ukraine is one big country in defiance," said Andriy Bondar, a modern Ukrainian writer. "Ukrainians are the most stubborn people in the world. ... The Kolobok ending is not for us."
The most prominent literary figures in Ukraine and Russia also embody the differences. Russia's great poet Aleksandr Pushkin preached liberty in his poems, but his family owned serfs. Ukraine's national symbol, the renowned poet Taras Shevchenko, was born a serf himself.
Having long specialized in agriculture and boasting some of Europe's most fertile soil, Ukrainians also have strong ties to their land.
Last spring, nearly 60 percent of Ukrainians planted potatoes on their personal plots, according to a poll conducted by the Razumkov Center. For many, growing food is just a way of getting by; for others, it's a tribute to ancestral traditions.
"The national ethos is this hard-working, honest peasant attached to the land," said Catherine Wanner, professor of history, anthropology and religious studies at Penn State University, who wrote a book about Ukraine's identity. "Part of the distinction (from Russians) is not wanting to be a colony, but also not wanting to be an imperial power."
The Russian national anthem glorifies Russia's might and grandeur. The Ukrainian anthem dreams of expelling enemies and finally being masters of their own land. In fact the central message of Ukraine's anthem is: Freedom is not dead yet.
Some in Ukraine's Russian-speaking east and south do feel nostalgic for the Soviet past. And many cherish ties with Russia, both economic and cultural.
But that does not make them Russian, argues Penn State's Wanner.
"Most people, regardless of which language is their first language, regardless of where they were born, nonetheless feel some kind of an attachment to the place where they live," Wanner said.
"And that's Ukraine."