Greg Smith, the former Goldman Sachs Group Inc employee who publicly resigned from the investment bank in a scathing op-ed in March, has written a memoir that will be published next month.

The book, titled "Why I Left Goldman Sachs," is set to be released on October 22, according to a statement from the book's publisher.

Smith quit as an executive director at Goldman after writing an op-ed in the New York Times on March 14 that accused the firm of routinely ripping off clients. He also wrote that top management had morphed Goldman into a "toxic and destructive" place that put profits ahead of all else.

Smith's book is expected to provide an inside look at how Goldman operates, based on his 12-year career at the bank.

Goldman, which conducted an internal review after Smith's op-ed ran, has said there was no substance to his assertions.

"Every day, some young professional, after a decade in a post-collegiate job, reassesses his or her career and decides to move on and do something else," Goldman spokesman David Wells said in a statement on Wednesday.

"Others can better judge whether Mr. Smith's particular career transition is of unique interest."

Grand Central Publishing, a unit of Hachette Livre, is publishing the book.

(Reporting by Lauren Tara LaCapra in New York; Editing by Dale Hudson and Phil Berlowitz)