Five to seven billion copies make the Bible the top seller of any book. Estimates on The Imitation, which was published in Latin c. 1418-1427, are uncertain, but there are about 750 extant manuscripts, that is, copies made around the publishing date. Thomas was born 1380 in Kempen, Germany, ordained 1413, and died 1471 in Zwolle, Netherlands, an old man of 91.
With 454 Amazon ratings the book is 4.7/5 and is divided into four parts providing detailed instructions: “Helpful Counsels of the Spiritual Life”, “Directives for the Interior Life”, “On Interior Consolation”, and “On the Blessed Sacrament”. A paperback edition costs about $10.