Hall Clement (Massachusetts, May 30th 1922 - October 29th 2003), of his true name Harry Clement Stubbs , is a American author of Science-fiction . He taught all his life sciences in Milton Academy; wanting to dissociate its career of writer of teaching, it chooses a shortened version of its first name like pseudonym. Its most known novel of the French-speaking public is probably Question of weight (also translated under the title of Mission revolved ).