Several copies of Charles Spencer's sensational memoir about his sister Princess Diana were stolen from a lorry just days before its exclusive publication in the Daily Mail. "Swan Song. Diana, My Sister" ("Swan song. Titled Diana, My Sister), the memoir promises a candid account of Diana's unhappy marriage to the then Prince of Wales, as well as the crisis within the British royal family since her death. Almost 30 years ago, as a result of a car accident. "Charles Spencer has been silent for almost 30 years and what he reveals about the king's reaction to Diana's death is truly terrifying," a publishing industry source said yesterday. However, another mystery is now brewing around the book. A truck carrying thousands of copies of the memoir was reportedly broken into in a parking lot in the Netherlands this week. Thieves stole just four copies of the book, all wrapped in a black plastic container to hide the contents. Publishing sources suggest that this could be a bold attempt to get hold of one of the most anticipated books of the year before its official release. Dutch police are investigating the mysterious break-in. Various theories about the incident are already being discussed in publishing circles, ranging from a random theft by ordinary criminals to a carefully planned operation by someone who knew exactly what to do. There was none in the truck. "This is extremely suspicious. Such a thing has never happened. This is probably the most anticipated book of the year, and the security measures around it were incredibly tight," said a source in the publishing industry. Another source emphasized that all possible precautions were taken to prevent leaks before publication. "Swan Song" is scheduled to be released next Tuesday. Before the memoir hits bookstores, the Daily Mail will publish an exclusive edition. The book is already called "historical" and "incredibly exciting". It is Charles Spencer's deeply personal account of his relationship with his older sister and his failed marriage. The memoir focuses particularly on the events of the fateful week after Diana's death in August 1997, when the House of Windsor became the center of an unprecedented wave of public grief and anger around the world. m. Buckingham Palace is expected to brace for a series of shocking revelations that could reopen the painful chapters of the former Prince and Princess of Wales' highly controversial separation and subsequent divorce. On the eve of the 30th anniversary of Diana's death, Charles Spencer has vowed that his book, which will be published worldwide and translated into 12 languages, will help correct the lies he says have been told about his sister. The 62-year-old earl made a moving and provocative speech at Diana's funeral in Westminster Abbey. The ceremony was broadcast live to about 2.5 billion people around the world.