Why has this book been written?
　　In October 1902, my friend Carruthers came to my office, and told me the story of the yachting trip that he and his friend Mr Davies had recently taken in the Baltic and the North Sea.
　　 The account of his adventures both astonished and alarmed me, and when he asked for my help in preparing this book for publication, I agreed readily. It is well known that Britain’s coastal defences are dangerously weak, so the secret information discovered by Carruthers and Davies is of great importance, and I fully support their wish to make this information public.
　　The difficulty they had was that an Englishman, from an old and famous family, would be shown in their story to be a traitor, and this would cause pain and misery to an innocent young lady, whom they are anxious to protect. The names Carruthers and Davies, therefore, are not their real ones, and the names of all other persons in this account have also been changed.
　　But why publish secret information of national importance? Should it not be kept secret, known only to the government, whose job is to make good use of such information?
　　Indeed, that would normally be the best thing to do, but not in this case. The government, although informed of the great danger facing this country, has chosen to do nothing – and that is the reason why this book has been written.
　　為什么要寫這本書呢？
　　1902年10月，我的朋友卡拉瑟斯來到我的辦公室，向我講述了不久前他和朋友戴維斯駕駛游艇在波羅的海和北海航行的故事。
　　卡拉瑟斯講述的冒險(xiǎn)經(jīng)歷讓我既吃驚又擔(dān)憂。所以，當(dāng)他請(qǐng)我?guī)退麑戇@本書來出版時(shí)，我欣然應(yīng)允。眾所周知，英國(guó)薄弱的海防危機(jī)四伏，卡拉瑟斯和戴維斯發(fā)現(xiàn)的秘密情報(bào)因此極為重要。所以，他們想要將這一情報(bào)公之于眾時(shí)，我全力支持。
　　麻煩之處在于，他們將在書中揭露一位出身名門世家的英國(guó)男子的叛國(guó)罪行，但這樣會(huì)傷害到一位他們竭力想要保護(hù)的無辜姑娘。因此，“卡拉瑟斯”和“戴維斯”兩個(gè)名字并不是真名，故事中其他人物的名字也都一一做了改動(dòng)。
　　可是，為什么要把國(guó)家級(jí)機(jī)密情報(bào)公之于眾呢？難道不該只把它局限在政府范圍內(nèi)，由政府來行使職責(zé)、充分利用此類情報(bào)嗎？
　　通常情況下這的確是最佳選擇，但這次不一樣。英國(guó)政府明明知道國(guó)家面臨嚴(yán)重危險(xiǎn)，卻選擇了不作為。因此，我們才寫了這本書。
　　……