A first condensed edition of Rumi’s Masnavi, but the first scholar to translate the Masnavi in its entirety – the complete translation was completed in 1940, nine years after the publication of this book, which contains selected tales.
About the Masnavi (from Wikipedia):
The Masnavi, also written Mathnawi, Ma’navi, or Mathnavi, is an extensive poem written in Persian by Jalal al-Din Muhammad Balkhi also known as Rumi, the celebrated Persian Sufi saint and poet. It is one of the best known and most influential works of both Sufism and Farsi Dari literature. The Masnavi is a series of six books of poetry that together amount to around 25,000 verses or 50,000 lines. It is a spiritual writing that teaches Sufis how to reach their goal of being in true love with God.
About R.A. Nicholson (from Wikipedia):
Reynold Alleyne Nicholson, or R. A. Nicholson (18 August 1868 – 27 August 1945), was an eminent English orientalist, scholar of both Islamic literature and Islamic mysticism and widely regarded as one of the greatest Rumi (Mewlana) scholars and translators in the English language.
Nicholson was lecturer in the Persian language at University College London from June 1902 to 1926, and Sir Thomas Adams’s Professor of Arabic at the University of Cambridge from 1926 to 1933. He is considered a leading scholar in Islamic literature and Islamic mysticism who exercised a lasting influence on Islamic studies. He was able to study and translate major Sufi texts in Arabic, Persian, and Ottoman Turkish to English. Nicholson wrote two very influential books: Literary History of The Arabs (1907) and The Mystics of Islam (1914).