Here's why:
* Critical Acclaim: The novel won the prestigious Whitbread Book of the Year Award in 2007.
* Stage Adaptation: The book was adapted into a critically acclaimed and hugely successful stage play, which has toured internationally.
* Film Adaptation: The play was further adapted into a critically acclaimed film by Steven Spielberg, further boosting its popularity.
* Enduring Popularity: War Horse continues to be a popular choice for schools and libraries, and remains a bestseller even years after its initial publication.
While other books like "The Butterfly Lion" and "Private Peaceful" are also widely loved and popular, "War Horse" arguably holds a special place in Morpurgo's bibliography due to its widespread recognition and impact.