Han Wudi neizhuan 漢武帝内傳 "Esoteric biography of Emperor Wu of the Han dynasty", shortly called Han Wudi zhuan 漢武帝傳, is a collection of phantastic stories traditionally attributed to the Later Han period 後漢 (25-220) historian Ban Gu 班固. The book was categorized as a miscellaneous biography (zazhuan 雜傳) or as a Daoist book, and it became only part of the category of novellas (xiaoshuo 小説) from the Ming period 明 (1368-1644) on. It was also during that time that authorship was first attributed to Ban Gu, but this is quite doubtful. Other persons, like Dongfang Shuo 東方朔 (who is himself said to have ascended to Heaven on the back of a dragon) and Guo Xian 郭憲, are also named as authors. The book consists of two juan "scrolls", one esoteric biography (neizhuan), and one "outer biography" (waizhuan 外傳).
The stories center on the life of the great Former Han period 前漢 (206 BCE-8 CE) Emperor Wu 漢武帝 (r. 141-87 BCE) from the times before his birth, and until his death. Through the performance of fasting rituals Emperor Wu was able to enounter the legendary Queen Mother of the West (Xiwangmu 西王母), which told him the secrets of immortality when she descended to the imperial palace on the 7th day of the 7th month (see Chinese calendar). The Queen Mother transmitted to Emperor Wu the chart Wumiao zhenxing tu 五廟真形圖, and her companion, the Shangyuan furen 上元夫人 "Lady of the Superior Origin", instructed him in the twelve arts to "numinous flight with the six jia hexagrams" (liujia lingfei 六甲靈飛). It was only the Emperor's desires (duo yu 多欲) that impeded him to become an immortal with the help of these instructions, and the scriptures handed over to him burnt on the Boliang Terrace 柏梁臺. The narrative quality of the book is very high so that it obtained a similar status in literature as the phantastic biography Mu Tianzi zhuan 穆天子傳. Large parts are written in rhymed prose, a stylistic method popular during the Southern Dynasties period 南朝 (420~589).
A lot of paragraphs are identical to that in the books Hanwu gushi 漢武故事 and Hainei shizhou ji 海內十洲記, and there are also some other sentences similar to such used during the Southern Dynasties period like the preface of the anthology Yutai xinyong 玉臺新詠. The Han Wudi neizhuan might therefore have been compiled around that time.
The "outer biography" has never been separately in circulation, but always as an appendix to the neizhuan. It is 14 paragraphs long and contains a lot of tales of contemporaries of Emperor Wu, but also such of later ages.
The book is included in the reprint series Shoushange congshu 守山閣叢書, Guang Han-Wei congshu 廣漢魏叢書, Wuchao xiaoshuo 五朝小說, Longwei mishu 龍威秘書, Shuofu 說郛, Wuyishizhai congchao 無一是齋叢鈔, the Siku quanshu 四庫全書, the Daoist Canon Daozang 道藏, and the Congshu jicheng 叢書集成.