Former President Bill Clinton is writing a new book about his post-presidential life, according to people familiar with the project, which was also confirmed by his spokesman.

While Mr. Clinton has been out of public office for nearly two decades, he and Hillary Clinton, the 2016 Democratic presidential nominee, have remained fixtures on the national political scene. The former president’s standing was in decline during the 2018 midterm elections, however, with few Democrats seeking to campaign with him because of controversy over policies like the 1990s crime bill and his personal misconduct with women, which has come under a new spotlight because of the #MeToo movement.

It is unclear how much of the book, if any, will deal with Mrs. Clinton’s two campaigns for president, or if Mr. Clinton will address the criticisms of his policy record or his personal behavior. He has mostly avoided those topics in his public appearances.

Paul Bogaards, an executive vice president for the publisher, Knopf Doubleday, said there was still no timetable for publication and that while the book is about Mr. Clinton’s post-White House life it is still too “early to assess what ground will be covered.” Angel Ureña, Mr. Clinton’s press secretary, declined to comment on the contents of book.