Wade–Giles was the system of transcription in the English-speaking world for most of the 20th century, used in standard reference books and in English language books published before 1979. It replaced the Nanking dialect-based romanization systems that had been common until the late 19th century, such as the Postal Romanization (still used in some place-names). In mainland China it has been entirely replaced by the Hanyu Pinyin system approved in 1958. Outside mainland China, it has mostly been replaced by Pinyin as well, even though Taiwan kept the Wade-Giles romanization of location names (for example Keelung) and family names (for example Chiang Ching-kuo).
Wade–Giles was developed by Thomas Francis Wade, a scholar of Chinese and a British ambassador in China who was the first professor of Chinese at Cambridge University. Wade published in 1867 the first textbook on the Beijing dialect of Mandarin in English, Yü-yen Tzŭ-erh Chi (simplified Chinese: 语言自迩集; traditional Chinese: 語言自邇集), which became the basis for the Romanization system later known as Wade–Giles. The system, designed to transcribe Chinese terms for Chinese specialists, was further refined in 1892 by Herbert Allen Giles (in A Chinese-English Dictionary), a British diplomat in China and his son, Lionel Giles, a curator at the British Museum.
Taiwan has used Wade–Giles for decades as the de facto standard, co-existing with several official but obscure romanizations in succession, namely, Gwoyeu Romatzyh (1928), Mandarin Phonetic Symbols II (1986), and Tongyong Pinyin (2000). With the election of the Kuomintang party in Taiwan in 2008, Taiwan officially switched to Hanyu Pinyin. However, many people in Taiwan, both native and overseas, use or transcribe their legal names in the Wade–Giles system, as well as the other aforementioned systems.
The tables below show the Wade–Giles representation of each Chinese sound (in bold type), together with the corresponding IPA phonetic symbol (in square brackets), and equivalent representations in Zhùyīn Fúhào (Bōpōmōfō) and Hànyǔ Pīnyīn.