哈尔·克莱蒙特，本名哈里·斯塔布斯，生于美国麻省，曾获哈佛天文学学士学位，二战时入伍，成为一名轰炸机飞行员。退伍后成为中学教师，长期教授科学课程。 克莱蒙特一生共创作了十五部长篇以及大量中短篇小说。1954年，《重力使命》开始在《惊奇科幻》连载，成为他的代表作，该书也是科幻史上硬科幻小说的代表。 克莱蒙特在科幻作家和读者中具有崇高的声望。他是1991年世界科幻大会的主宾，1998年入选科幻/奇幻名人殿，美国科幻奇幻作家协会于1999年星云奖颁奖仪式上授予他科幻大师称号。

For a profit -- and adventure -- Barlennan would sail thousands of miles across uncharted waters, into regions where gravity itself played strange tricks. He would dare the perils of strange tribes and stranger creatures -- even dicker with those strange aliens from beyond the skies, though the concept of another world was unknown to the inhabitants of the disk-shaped planet of...(展开全部)

For a profit -- and adventure -- Barlennan would sail thousands of miles across uncharted waters, into regions where gravity itself played strange tricks. He would dare the perils of strange tribes and stranger creatures -- even dicker with those strange aliens from beyond the skies, though the concept of another world was unknown to the inhabitants of the disk-shaped planet of...(展开全部)

His first new collection of short humor in fifteen years is classic Woody Allen. Zero Gravity is the fifth collection of comic pieces by Woody Allen, a hilarious prose stylist whose enduring appeal readers have savored since his classics Getting Even, Without Feathers, Side Effects, and Mere Anarchy. This new work combines pieces that have appeared in The New Yorker along with...(展开全部)

Quantum gravity is perhaps the most important open problem in fundamental physics. It is the problem of merging quantum mechanics and general relativity, the two great conceptual revolutions in the physics of the twentieth century. The loop and spinfoam approach, presented in this 2004 book, is one of the leading research programs in the field. The first part of the book discus...(展开全部)

Quantum gravity poses the problem of merging quantum mechanics and general relativity, the two great conceptual revolutions in the physics of the twentieth century. The loop and spinfoam approach, presented in this book, is one of the leading research programs in the field. The first part of the book discusses the reformulation of the basis of classical and quantum Hamiltonian ...(展开全部)

Gravity and Grace was the first ever publication by the remarkable thinker and activist, Simone Weil. In it Gustave Thibon, the farmer to whom she had entrusted her notebooks before her untimely death, compiled in one remarkable volume a compendium of her writings that have become a source of spiritual guidance and wisdom for countless individuals. On the fiftieth anniversary o...(展开全部)

在线阅读本书 On the fiftieth anniversary of the first English edition, this Routledge Classics edition offers the English reader the complete text of this landmark work for the first time ever.

本书的两位作者分别是美国宇航局（NASA）前顾问、哥伦比亚广播公司（CBS）科学部顾问里理查德•霍格兰德和NASA航空航天工程顾问麦克•巴拉。在本书中，他们披露了由NASA实施“阿波罗登月计划”时的“月球接收实验室数据和图片控制部”前主管肯•约翰斯顿提供的大量内部信息，向世人展示了一个被NASA蓄意隐瞒了40年的惊人事实：智能生物曾在人类之前到过月球，并留有遗迹。 理查德•霍格兰除此书外尚著有畅销书《火星上的建筑》。麦克•巴拉则著有《融合》。