When producers approached lyricist Steven Sater (“Spring Awakening”) to adapt Lewis Carroll’s “Alice’s Adventures in Wonderland” into a musical, his initial reaction was to recoil. His initial thought was that the book didn’t have a beginning, middle and an ending. But Sater pulled it off with his production of “Alice By Heart.”

After an off-Broadway run, someone suggested the unthinkable, to adapt the musical into a book. “Why would I transport the soul of this thing back into the form it had been in?” asked Sater.

Somehow, he went for it and worked on the adaptation. Where the Broadway show was a visual aesthetic with choreography, costumes and stunning set design, the book would have to rely on the power of imagination. “It would have to be about how to get through this dark time. I needed to focus on this girl in a tube station, and that the story was going to be conceived as an internal monologue,” explains Sater.

Once he had figured that out, Sater faced the challenge of what to retain from the show with how he could push that monologue. “I went from relying on the actors to bring all that was unsaid and immerse myself in all these parts that the show never could,” he says. “We were going through this heart and mind of this young girl, and I could go into her memory.”

In “Alice by Heart,” young Alice Spencer has taken shelter at a London tube station after the World War II blitz. Spencer wants to get to her friend Alfred, who is held in quarantine with tuberculosis. She’s told he might not survive, but Alice knows if she can get to him and they dive into the world of “Alice in Wonderland” together, he might just make it.

Sater wanted the book to communicate what Carroll’s classic meant to him. As a young boy, he spent much of his youth in hospitals and bedridden by illness, similar to Alfred. Books helped him get through hard times, much like Alice Spencer and Alfred use “Alice’s Adventures in Wonderland” to get through their darkest times.

“What is the use of a book without pictures or conversation?” Alice Spencer asks early on. And so, Sater found new illustrations as well as photos of people taking shelter in the tube stations.

The book, which was published in February, not only serves as a perfect companion piece to the musical but uniquely brings a classic back to life with a twist.

As Alice deals with adolescence and Sater stitches his story together, he appeals to the young adult readers of today. “I was being mindful of that,” he says. “I adopted this language from a 1940s girl, but with a literary style that felt contemporary.” Sater continues, “The story feels so urgent and so timely for me.”

Sater is no stranger to appealing to young adults — his Tony Award-winning “Spring Awakening” had a huge following with young people. “We had pretty much given up on this generation understanding poetry, and yet, all these young women showed up with lyrics on their jeans or legs. Here they were embracing the poetry of the show,” he says.

Now that Sater has written the book for “Alice by Heart,” he’s considering imagining a new production rather than just bringing it back. But first, there’s always the movie adaptation of “Spring Awakening.” They are in conversation “in a real way about the movie” is all Sater can say.