Amazon's web store has removed a best-selling book by a conservative author on the science and politics of transgenderism without notifying the author or giving him a reason why the book was deplatformed.

Ethics & Public Policy Center President Ryan T. Anderson, Ph.D., on Sunday discovered that his book, "When Harry Became Sally: Responding to the Transgender Moment" had been removed from Amazon's online store.

The book, which was an Amazon and Washington Post best-seller, surveys the debate on gender dysphoria, sex reassignment surgeries, and anti-discrimination law and considers biology, psychology, and philosophy to address what the public policy response should be for individuals who struggle to accept their bodies.

Anderson told TheBlaze that Amazon did not provide him with notice or an explanation for why his book was made unavailable to purchase. He only found out after people attempting to buy the book told him the listings on Amazon were taken down. Customers cannot purchase a used copy, the Kindle edition, or even the Audible version of Anderson's book.

"When Harry Became Sally: Responding to the Transgender Moment was released exactly three years ago (Feb 20, 2018 to be precise). It was attacked twice on the New York Times op-ed page. The Washington Post ran a hit piece on it that they then had to entirely rewrite to fix all their errors. It was obvious the critics hadn't read the book," Anderson said. "People who have actually read my book discovered that it was a thoughtful and accessible presentation of the state of the scientific, medical, philosophical and legal debates. Yes, it advances an argument from a certain viewpoint. No, it didn't get any facts wrong, and it didn't engage in any name-calling."

He noted that his book received widespread praise from various medical and psychology academics and professionals.

"It was praised by a who's who of experts: the former psychiatrist-in-chief at Johns Hopkins Hospital, a longtime psychology professor at NYU, a professor of medical ethics at Columbia Medical School, a professor of psychological and brain sciences at Boston University, a professor of neurobiology at the University of Utah, a distinguished professor at Harvard Law School, an eminent legal philosopher at Oxford, and a professor of jurisprudence at Princeton," said Anderson.

"None of that matters. It's not about how you say it, it's not about how rigorously you argue it, it's not about how charitably you present it. It's about whether you dissent from a new orthodoxy. Three years after publication, in the very same week that the House of Representatives is going to ram through a radical transgender bill amending the Civil Rights Act of 1964, Amazon erases my book opposing gender ideology from their cyber shelves. Make no mistake, both Big Government and Big Tech can undermine human dignity and liberty, human flourishing and the common good."

Anderson said that his publisher had contacted Amazon but had not yet received an explanation for why the book was deplatformed.

TheBlaze also reached out to Amazon, but comment for this article was not made available prior to publication.

Amazon was widely criticized by conservatives on social media for deplatforming the book.