Angels & Demons is a 2000 bestselling mystery-thriller novel written by American author Dan Brown and published by Pocket Books. It revolves around the quest of fictional Harvard University symbologist Robert Langdon to uncover the mysteries of a secret society called the Illuminati and to unravel a plot to annihilate Vatican City using destructive antimatter. The book uses the idea of a historical conflict between science and religion, particularly that between the Illuminati and the Roman Catholic Church.
The novel introduces the character Robert Langdon, who is also the protagonist of Brown's subsequent 2003 novel, The Da Vinci Code. It also shares many stylistic elements with its sequel, such as conspiracies of secret societies, a single-day time frame, and the Catholic Church. Ancient history, architecture, and symbolism are also heavily referenced throughout the book. A film adaptation was released on May 15, 2009, though it was set after the events of The Da Vinci Code film, which had been released in 2006.

What was lost will be found...

In this stunning follow-up to the global phenomenon The Da Vinci Code , Dan Brown demonstrates once again why he is the world's most popular thriller writer. The Lost Symbol is a masterstroke of storytelling - a deadly race through a real-world labyrinth of codes, secrets, and unseen truths...all under the watchful eye of Brown's most terrifying villain to date. Set within the hidden chambers, tunnels, and temples of Washington, DC., The Lost Symbol accelerates through a startling landscape toward an unthinkable finale.

As the story opens, Harvard symbologist Robert Langdon is summoned unexpectedly to deliver an evening lecture in the U.S. Capitol Building. Within minutes of his arrival, however, the night takes a bizarre turn. A disturbing object - artfully encoded with five symbols - is discovered in the Capitol Building. Langdon recognizes the object as an ancient invitation...one meant to usher its recipient into a long-lost world of esoteric wisdom.

When Langdon's beloved mentor, Peter Solomon - a prominent Mason and philanthropist - is brutally kidnapped, Langdon realizes his only hope of saving Peter is to accept this mystical invitation and follow wherever it leads him. Langdon is instantly into a clandestine world of Masonic secrets, hidden history, and never-before-seen locations - all of which seem to be dragging him toward a single, inconceivable truth.

As the world discovered in The Da Vinci Code and Angels & Demons , Dan Brown's novels are brilliant tapestries of veiled histories, arcane symbols, and enigmatic codes. In this new novel, he again challenges readers with an intelligent, lightning-paced story that offers surprises at every turn. The Lost Symbol is exactly what Brown's fans have been waiting for...his most thrilling novel yet.
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虔诚的上帝信徒——欧洲原子核研究组织的杰出科学家列奥纳多·维特勒毕生致力于以科学的手段证明神的存在。他和其养女、神秘妩媚的科学家维特多利亚在实验室里进行高度机密的试验，成功地制造出了一种极其强大的能量——“反物质”。
在这个重大发现尚未对外公布时，列奥纳多在实验室里惨遭杀害，一颗眼珠被凶手挖走，胸口上赫然印着一个神秘的标记——“光照派”！更令人震惊的是，藏在地下的反物质不翼而飞。哈佛大学的符号学专家罗伯特·兰登应欧洲原子核研究组织首领之邀，前来调查这个神秘的符号。就在他到达的当天，失踪的反物质在梵蒂冈城地下某处被人发现。离开了实验室的反物质，会在二十四小时之后自行爆炸。这天正是天主教教皇选举日。来自世界各地的天主教首领会聚在梵蒂冈城，藏在地下的反物质就如同一枚定时炸弹，如不能及时找到，整个梵蒂冈城便会在顷刻间灰飞烟灭。
形势刻不容缓，兰登与维特多利亚一起踏上了前往梵蒂冈的冒险之旅……

世界上最隐秘的情报部门——美国国家安全局（NSA）斥巨资建造了一台可以破解一切密码的机器——万能解密机。这台超级电脑帮助NSA挫败了无数恐怖分子的阴谋，但这台电脑也能截获普通人的电子邮件。这个世界已没有隐私和秘密可言！
NSA前程序设计师远诚友加针锋相对地推出了“数字城堡”，他声称这是具有不可破解的密码的加密软件，并以此要挟NSA，要求他们向世人宣布万能解密机的存在。不料，远诚友加在西班牙意外死亡，而刻有口令的戒指却神秘失踪。
NSA首席密码破解专家苏珊·弗莱切与男友——语言学家戴维·贝克猝不及防地被卷入了这一事件中。两人各自在扑朔迷离的情境中经历了险象环生的一幕幕……

美国总统大选在即，共和党总统候选人参议员塞奇威克·塞克斯顿猛烈抨击现任总统的航空航天政策，得到了大多数美国选民的支持，形势对现任总统的连任极为不利。就在这个关键时刻，国家航空航天局向总统报告了一项惊人的科学成果：他们在北冰洋之下有重大发现……这个发现对美国的航空航天政策和迫在眉睫的总统大选都意义重大。
为了证实这项非同小可的发现，总统派遣国家勘测局的情报分析员，同时也是总统竞选对手的千金雷切尔·塞克斯顿前往冰川覆盖、气候恶劣的北极圈，与极富个人魅力的偶像型科学名人迈克尔·托兰以及几位来自不同领域的科学家一道对之进行核查。雷切尔和迈克尔意外地发现了一个不可思议的科学骗局。
还没来得及跟总统取得联系，雷切尔和迈克尔就遭到了三角洲特种部队的几个神秘杀手的袭击。这些杀手被一只企图不顾一切掩盖真相的幕后黑手操纵。雷切尔和迈克尔开始了惊险刺激的逃亡之旅，支撑他们活下来的最后一丝希望就是要查明真相……

哈佛大学的符号学专家罗伯特·兰登在法国巴黎出差期间的一个午夜接到一个紧急电话，得知卢浮宫博物馆年迈的馆长被人杀害在卢浮宫的博物馆里，人们在他的尸体旁边发现了一个难以捉摸的密码。兰登与法国一位颇有天分的密码破译专家索菲·奈芙，在对一大堆怪异的密码进行整理的过程当中，发现一连串的线索就隐藏在达芬奇的艺术作品当中，深感震惊。这些线索，大家都清楚可见，然而却被画家巧妙地隐藏起来。兰登无意之中非常震惊地发现，已故的博物馆馆长是峋山隐修会（Priory of sion）的成员--这是一个真实存在的秘密组织，其成员包括艾撒克・牛顿爵士、波提切利、维克多·雨果与达芬奇，这无疑给他们增加了风险。兰登感觉到他们是在找寻一个石破天惊的历史秘密，这是个数世纪以来就证明了的既能给人启迪又很危险的秘密。在这场足迹遍及巴黎以及伦敦的追逐中，兰登与奈芙发现他们在跟一位始终不露面的幕后操纵者斗智斗勇。他们必须解开这个错综复杂的谜团，否则，峋山隐修会掩盖的秘密，那隐藏了多年的令人震惊的古老真相，将永远消逝在历史的尘埃之中。