A brand new book from the late Dr. Seuss hits bookstores today, and is already the number-one seller for books on Amazon. It was discovered two years ago in a box in the author and illustrator’s home office in La Jolla, California.

The planned publication of the lost manuscript was announced in February, and has been eagerly awaited ever since. What Pet Should I Get? is now the 47th children’s book from Theodor Seuss Geisel (aka Dr. Seuss), who died in 1991 at age 87.

Dr. Seuss, What Pet Should I Get?
Photo: courtesy Random House Children’s Books.

“Dr. Seuss is more popular now than he was during his lifetime,” Bill Dreyer, director and curator of the Art of Dr. Seuss, the author and illustrator’s estate and collection, told CBS News. “In the 25 years since he’s now been gone, another 450 million books have been sold.”

Dr. Seuss, What Pet Should I Get?
Photo: courtesy Random House Children’s Books.

What Pet Should I Get? joins Harper Lee’s recently-released Go Set a Watchman, another highly-anticipated, long-unknown and -unpublished work, on the Amazon Best Sellers list.

But where many argue that Lee’s second novel, an early, abandoned draft of her iconic To Kill a Mockingbird, would have been better left to her archives, What Pet I Get? appears to be an addition to the Seuss canon more-widely accepted as genuine, and a worthy follow-up to his last new work, Oh, the Places You’ll Go!, which was published 25 years ago.

The charming picture book, written in Seuss’s signature simple rhyming style, follows the brother and sister from the classic One Fish, Two Fish, Red Fish, Blue Fish as they struggle to choose what kind of animal they want to adopt. It is believed to date from between 1958 and 1962.

Dr. Seuss, What Pet Should I Get?
Photo: courtesy Random House Children’s Books.

At the pet store, the siblings quickly become equally enamored with the prospect of bringing home a dog, a cat, a rabbit, or a bird. As the tale progresses, they imagine the possibilities of increasingly more fantastical, Seussian creatures, further complicating their decision.

The story ends on a cliffhanger as the children carry out their new pet in a basket, the lid covering all but the creature’s eyes.

Dr. Seuss, What Pet Should I Get?
Photo: courtesy Random House Children’s Books.

“The book is, if not top-flight Seuss, a very good example of his particular genius for distilling both the spirit of his times and the timeless mind-set of children,” wrote Maria Russo in her review for the New York Times, praising the author for making “learning to read an adventure, a club children would actually want to belong to.”

Dr. Seuss, What Pet Should I Get?
Photo: courtesy Random House Children’s Books.

An audio book edition is narrated by Rainn Wilson. Random House has announced plans to release two additional Seuss books based on manuscripts discovered alongside What Pet Should I Get?