Bob Dylan apologized to fans who paid $600 for limited-edition copies of his latest book, only to discover the signatures inscribed on them had been done using an autopen.

Publishers Simon & Schuster offered 900 copies of The Philosophy of Modern Song complete with the author’s autograph, but when buyers realized Dylan hadn’t physically signed them himself – meaning the edition had a much lower value to collectors – they initially refused to offer refunds before finally caving in.

In a new social media post, Dylan wrote: “I’ve been made aware that there’s some controversy about signatures on some of my recent artwork prints and on a limited-edition of Philosophy of Modern Song. I’ve hand-signed each and every art print over the years, and there’s never been a problem.”

He continued: “However, in 2019 I had a bad case of vertigo and it continued into the pandemic years. It takes a crew of five working in close quarters with me to help enable these signing sessions, and we could not find a safe and workable way to complete what I needed to do while the virus was raging. So, during the pandemic, it was impossible to sign anything and the vertigo didn’t help.”

He said that as “contractual deadlines” approached, the autopen idea was suggested, “along with the assurance that this kind of thing is done ‘all the time’ in the art and literary worlds.” He added: “Using a machine was an error in judgment and I want to rectify it immediately. I’m working with Simon & Schuster and my gallery partners to do just that.” He signed off: “With my deepest regrets, Bob Dylan.”

Published earlier this month, The Philosophy of Modern Song contains 66 essays on tracks written by other artists, and took him 12 years to bring to market. It’s his first book since he won the Nobel Prize for Literature in 2016 for “having created new poetic expressions within the great American song tradition.”