John Wycliffe (also spelled Wyclif, Wycliff, Wiclef, Wicliffe, Wickliffe; c. 1331 - 1384) was an English Scholastic philosopher, theologian, lay preacher, translator, reformer and university teacher at Oxford in England. He was an influential dissident in the Roman Catholic Church during the 14th century. His followers were known as Lollards, a somewhat rebellious movement, which preached anticlerical and biblically-centred reforms. The Lollard movement was a precursor to the Protestant Reformation. He has been characterized as the evening star of scholasticism and the Morning Star of the Reformation. He was one of the earliest opponents of papal authority over secular power.
Wycliffe was also an early advocate for translation of the Bible into the common language. He completed his translation, now known as Wycliffe's Bible, directly from the Vulgate into vernacular English in the year 1382. It is probable that he personally translated the Gospels of Matthew, Mark, Luke, and John; and it is possible he translated the entire New Testament, while his associates translated the Old Testament. Wycliffe's Bible appears to have been completed by 1384, with additional updated versions being done by Wycliffe's assistant John Purvey and others in 1388 and 1395.
It doesn't have to be said that John Wyclif was instrumental in the early stages of the reformation. His English works seem to be the only ones currently available even though his most influential were the ones he composed in Latin. Jan Hus (the founder of the first true Protestant church) was heavily indebted to Wyclif, so much so that today we would probably consider him guilty of plagiarism; but it is doubtful that Wyclif would have seen it that way since both Hus and Wyclif always stated that they were just teaching the Gospel. It also seems that Wyclif and Hus were both indebted to Gratian's decretals to some extent. Most of the writings contained here are Wyclif's (and maybe other Wyclifite writings mistakenly attributed to Wyclif) polemics against: indulgences, immorality of priests, abuses of the poor by clergy, instituting of non-Biblical dogmas, priests not being dedicated to poverty etc. Excellent book and really a must for any library that features influential Christian works. It must be stated upfront that this book is in 14th century Old English. I did not know this when I purchased it. It takes a little while to read it fluently. There is a glossary and a marginal synopsis which makes it easily doable if one wants to take the time to do it, otherwise I would say that you may want to find a modern English translation because at first look 14th century English looks almost like a foreign language.
Placeholder for the letter from Paul to Laodicea referenced in Colossians (though current scholarship doubts the authenticity; and so its inclusion in the Wycliffe Bible is thrown into question)