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Masked Hero
How Wu Lien-teh Invented the Mask That Ended an Epidemic


NCTAsia Freeman Award Honorable

Mention 2023



Outstanding Science Trade Books for

Students K–12


Dr. Shan Woo Liu's new children's book is about a real-life masked hero, Dr. Wu Lien-teh, who ended a deadly pandemic by getting everyone to wear masks. 


Masked Hero is on the Bank Street College of Education’s 2024 Best Children’s Books of the Year List

​Published by Candlewick/MIT Kids. 

Release date: October 10, 2023.

Books can be purchased at your local bookstore (ISBN: 1536234540/ 9781536234541 if not in stock)or from any of these online Penguin Random House Distributors.


The mother and daughter co-authors, both descendants of their subject, trace the course of Wu’s career... They deftly cast light on medical issues and the racism Wu faced, drawing parallels between past and present... Chockablock with timely themes and connections to recent world-shaking events.—Kirkus Reviews

Woo Liu’s great-grandfather, physician Wu Lien-teh (1879–1960), stars in a biography that focuses on its protagonist’s implementation of face masks to combat disease.... The gauze masks that the physician innovates end the outbreak, and later prove useful during the 1918 flu and as a prototype for Covid-combatting masks that “became part of everyday life.” 

—Publishers Weekly

Liu, herself a physician, traces the life of her great-grandfather, Wu Lien-teh, often touted as the father of modern medicine in China... Liu's straightforward... text shows Lien-teh withstanding the headwinds of racism and peer skepticism and charts the legacy of his epidemiological breakthrough. 

The Horn Book

This smoothly written picture book—written by Wu's great-granddaughter, an American doctor, and inspired by her daughter’s first-grade writing assignment—introduces a heroic researcher whose practical approach to disease prevention saved many lives, notably during the 1918 influenza pandemic. Wee’s pleasing digital art illustrates the story within effective period settings. This picture-book biography showcases a significant, lesser-known East Asian scientist/physician.

Masked Hero is a children's book. It is also a book of Liu's family history. The book is based on a real story about Dr. Lien-teh Wu who was Liu's great-grandfather from her father's side. Wu invented a medical mask in 1911 to fight the plague in Harbin, China. Because of the masks invented by Wu, the Harbin plague ended in less than 4 months. Wu encouraged people in Harbin of China over 100 years ago to wear face coverings designed by him with layers of cloth and gauze. It was the first version of the N95 mask.

—Wind Newspaper

[Masked Hero is] an uplifting story that, hopefully, will spread the word that the decision to wear a mask is a positive decision, one that shows ones support for your community. 

—The Nonfiction Detective 

This informative and beautifully presented picture book gives us the story of one of those genuine heroes and, in the words of the book’s sub-title, shows us ‘How Wu Lien-teh Invented the Mask That Ended an Epidemic’. 

—The Letterpress Project

This book is penned by Wu’s great-granddaughter, who shares the struggles her ancestor went through, facing discrimination from non-Chinese and ridicule for ideas that people of his time couldn’t understand fully... The story of Dr. Wu is an essential read for children today, helping them connect a moment in their present to people who lived over a century ago.

—The Reading Circle 

Masked Hero is the story of a doctor’s determination to save people’s lives. This fascinating picture book biography follows Wu Lien-teh from childhood through his career. Readers will be amazed at his ingenuity that earned him a nomination for the Nobel Prize in 1935. Author Shan Woo Liu’s text is comfortable and informative. And Lisa Wee’s digital art captures both time and place perfectly.

—Cracking the Cover 

There [Wu Lien-Teh] overcame discrimination to promote trailblazing measures that will be familiar to readers today – including encouraging people to wear a face covering he designed from layers of cloth and gauze: the first version of the N95 mask. Written by Wu Lien-teh’s great-granddaughter, who is now an ER doctor who relied on his life-saving invention during a pandemic a century later, and charmingly illustrated by Lisa Wee, this is an inspiring and fascinating biography about an unknown hero of science.

—Books Up North

‘When we wear a mask to stop a disease, we are all heroes – just like Wu Lien-teh!’ conclude the authors. Neatly describing the medical and racist issues Lien-teh faced, as well as drawing parallels between the past and recent times, these authors pay tribute to an amazing person who still hasn’t really received all the credit he deserves... An inspiring pictorial STEM biography to add to classroom collections.

—Red Reading Hub



Press Coverage:

World Journal Newspaper 10/6/23 

Reading Eagle

“Masked Hero: How Wu Lien-teh Invented the Mask That Ended an Epidemic” is a fascinating, inspirational story in every way.

Boston Globe 10/21/23

A century later, Liu fought against the COVID-19 pandemic, as an emergency medicine physician at Massachusetts General Hospital. In response to what she saw as a limited representation of Asian heroes in children’s literature, Liu began another mission, this time, bolstered by the story of her great-grandfather. In her new picture book, “Masked Hero: How Wu Lien-teh Invented the Mask That Ended an Epidemic,” Liu and her daughter, Kaili Liu Gormley, share Wu’s fascinating history — from his struggle against disease and discrimination to his ultimate triumph as an innovator. (His impressive career later earned him a Nobel Prize nomination and a Google Doodle.)


The N-95 and other respiratory masks have become a common part of our lives because of the COVID-19 pandemic. But for Dr. Shan Woo Liu, the face mask is also a piece of family history.

Liu, an emergency medicine physician at Massachusetts General Hospital, wrote a book along with her daughter, Kaili, called "Masked Hero." It tells how Liu's great-grandfather, Dr. Wu Lien-teh, ended a plague by creating the predecessor of what is now the N-95 mask more than a century ago.

Dr. Liu joined Radio Boston to talk about Dr. Wu’s story and how his legacy lives on today.

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