A congshu 叢書 "thicket book" collectaneum is a collection of writings in one series. The writings often belong to a certain category or have a common theme but can also be of special interest for the compiler of the collectaneum.
The origin of congshu are the early encyclopedias from the Tang period 唐 (618-907). The word congshu does not necessarily appear in the title but can either be replaced by similar terms like congkan 叢刊, congke 叢刻, huike 彙刻 etc., or be left out at all. Lu Guimeng's 陸龜蒙 book Lize congshu 笠澤叢書 from the Tang period, on the other hand, is one book, and no collectaneum. The books assembled in collectanea are often rare and only to be found in private libraries.
The oldest collectanea are Zhu Shengfei's 朱勝非 Ganzhuji 紺珍珠集, Yu Dingsun's 俞鼎孫 Ruxue jingwu 儒學警悟, and Zuo Gui's 左圭 Baichuan xuehai 百川學海 from the Song period 宋 (960-1279). These collectanea established a tradition perpetuated during the Ming and Qing periods.
The most important Ming period 明 (1368-1644) collectanea are He Tang's 何鏜 Han-Wei congshu 漢魏叢書 (including 100 books), Cheng Rong's 程榮 Han-Wei congshu (38 books), Shang Weijun's 商維濬 Baihai 稗海, Li Shi's 李栻 Lidai xiaoshi 歷代小史, Jiang Nan's 姜南 Rongtang zazhu 容塘雜著, the anonymous Shuozuan 說纂, the Wenfang xiaoshuo 文房小説 by Master Gu from Yinshan 陰山顧氏, Chen Jiru's 陳繼儒 Baoyantang miji 寶顏堂秘笈, Hu Wenhuan's 胡文煥 Gezhi congshu 格致叢書, and Zhong Renjie's 鍾人傑 Tang-Song congshu 唐宋叢書.
There are two traditions among the Ming period collecteanea. The one follows the example of the Baichuan xuehai (100 books) and extended this collectaneum, like Wu Yong's 吳永 Xu baichuan xuehai 續百川學海 (120 books) and Feng Kebing's 馮可賓 Guang baichuan xuehai 廣百川學海 (130 books).
Many collectors imitated the pattern of choice adopted in the Baichuan xuehai and assembled the most important or most interesting writings of the "hundred masters" or historiographical writings. The most important examples of this kind of collectaneum are Zheng Zi's 鄭梓 Mingshi xueshan 明世學山, Gao Mingfeng's 高鳴鳳 Jinxian huiyan 今獻彙言, Wang Wenlu's 王文祿 Bailing xueshan 百陵學山, Wu Guan's 吳琯 Jingu yishi 今古逸史, Zhou Ziyi's 周子義 Zihui 子彙, Zhou Lüjing's 周履靖 Yimen guangdu 夷門廣牘, Shen Jiefu's 沈節甫 Jilu huibian 紀錄彙編, or Fan Weicheng's 樊維城 Yanyi zhilin 鹽邑志林.
The other tradition is that of the collectaneum Shuofu 說郛 compiled by Tao Zongyi 陶宗儀 which does not include whole books but only the most interesting parts of it. The 100 chapters (juan "scrolls") long Shuofu contains countless excerpts from more than 1,000 books which are longe since lost. During the 1450s a 120 juan-long Shuofu was printed, and in the late 17th century a 200-juan long version was printed. Both were not the originals by Tao Zongyi but were "wild" prints of bad quality, the latter organized by Tao Ting 陶珽. Around the same time the printing shop Jiangnan shufang 江南書坊 published a crippled and reorganised version of the Shuofu. Other publishers even gave other titles to their reprints but retained the name of Tao Zongyi, like the versions Jinnang xiaoshi 錦囊小史, Shuibian linxia 水邊林下, or Qunfang qingwan 群芳清玩. Other publications even include newly added maps and illustrations, like Chen Luru's Bagong youxi congdu 八公遊戲叢讀 and Tu Benjun's 屠本畯 Shanlin jingji ji 山林經濟籍.
Although the collectanea of the Ming period deserve high attention because they preserved a lot of rare sources the quality of the texts is often not very high because the publishers often altered or abbreviated texts.
The late Ming period scholar Mao Jin 毛晉 was the first publisher of collectanea who earnestly undertook text-critical work and tried to reconstruct the original wordings of many texts from the Han 漢 (206 BCE-220 AD) and Tang periods in his collectaneum Jindai mishu 津逮秘書. A similar work has already been acheived in Hu Zhenheng's 胡震亨 Mice huihan 秘冊彙函 (Bice huihan 袐冊彙函).
From the Qing period 清 (1644-1911) on the rules for the composition of a congshu became very strict, only whole books were to be included, and the term congshu appears more often in the title. There are numerous collectanea specializing in writings from Ming period authors, like the anonymous Mingji yeshi huibian 明季野史彙編, Ye Tengxiang's 葉騰驤 Chongzhen congshu 崇禎叢書, Feng Menglong's 馮夢龍 Jiashen jishi 甲申紀事, or the collectaneum Jingshe yishi 荊蛇逸史 by a master called Chenhu yishi 陳湖逸士.
The Qing period was a time of vivid compilation of collectanea. There were large officially compiled collectana of which the Siku quanshu 四庫全書 is the most famous. Another is a collection of books stored in the imperial library, the Wuyingdian juzhenban congshu 武英殿聚珍版叢書.
Yet there is also a vast amount of privatly published collectanea, like Cao Rong's 曹溶 Xuehai leibian 學海類編, Zhao Chao's 趙潮 Zhaodai congshu 昭代叢書, Bao Tingbo's 鮑廷博 Zhibuzuzhai congshu 知不足齋叢書, Sun Xingyan's 孫星衍 Pingjinguan congshu 平津館叢書, Zhang Haipeng's 張海鵬 Jieyueshanfang huichao 借月山房彙鈔, Gu Yuan's 顧沅 Ciyantang congshu 賜硯堂叢書, Wu Yuanwei 伍元薇 and Wu Chongyao's 伍崇曜 Lingnan yishu 嶺南遺書, Huang Zhimo's 黃秩謨 Xunmintang congshu 遜敏堂叢書, Wu Chongyao's Yueyatang congshu 粵雅堂叢書, Ma Guohan's 馬國翰 Yuhan shanfang ji yishu 玉函山房輯佚書, Gu Xiang's 顧湘 Xiaoshishanfang congshu 小石山房叢書, Qian Xizuo's 錢熙祚 Shoushange congshu 守山閣叢書, Li Xiling's 李錫齡 Xiyinxuan congshu 惜陰軒叢書, Ding Bing's 丁丙 Wulin zhanggu congbian 武林掌故叢編, Cai Erkang's 蔡爾康 Xieyu congshu 屑玉叢書, or the Shenbaoguan congshu 申報館叢書 published in Shanghai.
The collectanea published in the 20th century often concentrate on Ming period authors, like the Guxue congkan 古學叢刊 by Deng Shi 鄧實 and Miao Quansun 繆荃孫, Deng Shi's Guocui congshu 國粹叢書 and Fengyulou congshu 風雨樓叢書, Sun Yuxiu's 孫毓修 Hanfenlou biji/miji 涵芬樓秘笈, Zhang Shouyong's 張壽鏞 Siming congshu 四明叢書, and Zheng Zhenduo's 鄭振鐸 Xuanlantang congshu 玄覽堂叢書.
The large publishing houses of China created quite voluminous collectanea containing huge collections of authors from all periods of time. Those are the Sibu congkan 四部叢刊 and Congshu jicheng (chubian) 叢書集成初編 published by the Commercial Press 商務印書館, and the Sibu beiyao 四部備要 published by the Zhonghua Book Company 中華書局.
The Sibu congkan contains facsimile copies of old Song period printings. Very worth mentioning is the collectaneum Baibu congshu 百部叢書, a recreation of the Congshu jicheng chubian and published by the Yiwen yinshuguan press 藝文印書館 in 1965-1970, which contains in itself one hundred collectanea. Of several of these large collectanea different editions exist, like for instance the Sibu beiyao which exists in a traditional thread-bound edition and an edition of small modern paperback volumes. Some of the collectanea follow the traditional four categories into which Chinese literature was divided.