《汉书》，又名《前汉书》，中国古代历史著作。东汉班固所着，是中国第一部纪传体断代史。沿用《史记》的体例而略有变更，改「书」为「志」，改「列传」为「传」，改「本纪」为「纪」，无「世家」。全书包括纪十二篇，表八篇，志十篇，传七十篇，共一百篇，记载了上自西汉汉高祖元年（前206年），下至新朝地皇四年（23年），共230年历史。《汉书》语言庄严工整，多用排偶，遣辞造句典雅远奥，与《史记》平畅的口语化文本形成鲜明对照。中国纪史方式自《汉书》以后，都仿照其体例，纂修了纪传体的断代史。

自班彪起即以着《汉书》为己任，经过二十余年努力，班固完成了《汉书》的主要部分。汉和帝永元元年（89），班固随从窦宪出击匈奴，参预谋议。后因事入狱，永元四年死在狱中。时《汉书》还有八表和《天文志》没有写成，汉和帝命班昭（曹大家）入东观藏书阁补作，马续协助班昭作了《天文志》。故汉书前后历经四人之手完成，历时四十多年。汉书注疏中，最著名者有唐颜师古注、清王先谦补注。

The Book of Han or History of the Former Han is a history of China finished in 111, covering the Western, or Former Han dynasty from the first emperor in 206 BCE to the fall of Wang Mang in 23 CE. It is also called the Book of Former Han.

The work was composed by Ban Gu, a court official, with the help of his sister Ban Zhao, continuing the work of their father, Ban Biao. They modeled their work on the Records of the Grand Historian, a universal history, but theirs was the first in this annals-biography form to cover a single dynasty. It is the best source, sometimes the only one, for many topics in this period. A second work, the Book of the Later Han covers the Eastern Han period from 25 to 220, and was composed in the fifth century by Fan Ye (398–445).