Two Trips to Gorilla Land and the Cataracts of the Congo, both volumes in a single file

According to Wikipedia: "Captain Sir Richard Francis Burton KCMG FRGS (19 March 1821 – 20 October 1890) was a British explorer, translator, writer, soldier, orientalist, ethnologist, spy, linguist, poet, fencer and diplomat. He was known for his travels and explorations within Asia, Africa and the Americas as well as his extraordinary knowledge of languages and cultures. According to one count, he spoke 29 European, Asian, and African languages. Burton's best-known achievements include travelling in disguise to Mecca, an unexpurgated translation of One Thousand and One Nights (also commonly called The Arabian Nights in English after Andrew Lang's abridgement), bringing the Kama Sutra to publication in English, and journeying with John Hanning Speke as the first Europeans led by Africa's greatest explorer guide, Sidi Mubarak Bombay, utilizing route information by Indian and Omani merchants who traded in the region, to visit the Great Lakes of Africa in search of the source of the Nile. Burton extensively criticized colonial policies (to the detriment of his career) in his works and letters. He was a prolific and erudite author and wrote numerous books and scholarly articles about subjects including human behaviour, travel, falconry, fencing, sexual practices, and ethnography. A unique feature of his books is the copious footnotes and appendices containing remarkable observations and unexpurgated information."