怡府藏書未受到應有的關注。怡府實是清代乃至整個中國藏書史上藏書最多的重要藏書家之一。學界對其藏書的來源、流向、規模及刻書情況、《怡府書目》的編纂時間、怡府主人名號等均存在錯誤的認識，尤其是其藏書來自徐乾學、季振宜的舊說，以及將怡府安樂堂、明善堂與乾隆樂善堂相混淆等錯誤，被學界陳陳相因，沿誤至今。本文利用新發現的怡府書目《影堂陳設書目錄》，及其他新的珍貴材料，並對分藏世界二十餘圖書館的怡府舊藏書籍數百種予以考察，對怡府藏書做系統的考論，在怡府藏書之規模、書目之編纂、藏書之聚散及怡府藏書樓名、刻書情況等各個方面提出新的認識。

The Yi Mansion Library is regarded as one of the most important and largest collection of books in the Qing dynasty and even throughout the history of private libraries in China. However, it has not been given the attention it deserves. The academic field has long harbored misconceptions on the sources, circulation, and size of the library, as well as the time the Catalog of the Yi Mansion Library was compiled, the courtesy names of the masters of Yi Mansion, etc. (especially regarding the fact that many books came from Xu Qianxue and Ji Zhenyi’s old collections). Furthermore, the Anle Tang of the Yi Mansion is sometimes mistaken for Emperor Qianlong’s Mingshan Tang or Leshan Tang. With the help the newly-found book The Catalog of Books Displayed in Ying Tang in Yi Mansion and other new materials, this essay sets forth some new ideas on different aspects of the Yi Mansion Library by surveying hundreds of books from the library currently found in more than twenty libraries throughout the world and investigating it in a systematic way.