Gù Yánwǔ 顧炎武 (1613–1682), original name Jiàng 絳, zì Níngrén 寧人, hào Tínglín 亭林 (after Tínglín lake in his native Kūnshān 崑山, Sūzhōu prefecture, modern Jiāngsū), self-styled also Jiǎngshānyōng 蔣山傭, was the founding figure of the Qīng evidential-research school (Hànxué pài 漢學派) and one of the “Three Great Confucians of the Early Qīng” (alongside Huáng Zōngxī 黃宗羲 and Wáng Fūzhī 王夫之 (王夫之)). The Sìkù compilers state plainly that “of those at the founding of our dynasty whose learning had a real grounding, none surpassed Yánwǔ” (guó chū chēng xué yǒu gēndǐ zhě, yǐ Yánwǔ wèi zuì 國初稱學有根柢者以炎武為最). Lifedates 1613–1682 firm; CBDB id 34252.
A late-Míng zhūshēng 諸生; took a leading role in the Sūzhōu-area Míng resistance after 1644, refused to serve the Qīng, and after the deaths of his foster mother Wángshì 王氏 (who starved herself to death rather than accept Qīng rule) and his teacher Zhōu Yǒngfú 周永輔 spent the rest of his life as a wandering scholar moving between northern and central China, accumulating notes and inscriptions at every site he visited. His final years were spent at Huáyīn 華陰 (Shǎnxī).
His principal work, the Rì zhī lù 日知錄 (KR3a0091) — a vast notebook of philological, historical, geographic, and political observations — is the foundational text of kǎo zhèng 考證 (“evidential research”) learning, and through Qián Dàxīn 錢大昕 and Zhāng Zhīdòng 張之洞’s reception (Wilkinson, Chinese History §16.3.3, §55582) supplied the Qīng Hànxué movement with both its method and its programmatic framing. Other monumental works include the geographic compendium Tiānxià jùnguó lìbìng shū 天下郡國利病書 (a vast collection of Míng provincial gazetteer extracts arranged by jurisdiction); the Zhàoyù zhì 肇域志 (geographic gazetteer); the historical-phonological masterwork Yīn xué wǔ shū 音學五書 (with its core Shī běn yīn 詩本音 and Yì yīn 易音), establishing the foundation of Qīng historical phonology by reconstructing Old Chinese rhyme categories from the Shī jīng and bronze inscriptions; the epigraphic Jīnshí wénzì jì 金石文字記; and a series of focused commentaries including the Zuǒ zhuàn Dù jiě bǔ zhèng 左傳杜解補正 (KR1e0096) — a 3-juǎn supplement and corrective to Dù Yù’s 杜預 (杜預) classical Zuǒ commentary, which the Sìkù tíyào praises as having “swept away factional positions and held the balance of right and wrong” (sǎo chú ménhù, néng chí shìfēi zhī píng 掃除門户，能持是非之平).
A short biography (xiǎo zhuàn 小傳) of him by Lǐ Guāngdì 李光地 (李光地) is preserved in the Róngcūn jí 榕村集. CBDB id 34252.