The celebration of the Latin or Tridentine mass, otherwise known as the Extraordinary Form, is an increasingly common practice in Roman Catholic churches throughout the world. Once the only rite in use which Catholics around the world knew from childhood, its usage ended with the Second Vatican Council's ruling that liturgy should be celebrated in peoples' own languages. The Latin mass thus became the preserve of various traditionalist societies.Two years ago the Pope declared that the celebration of the Latin mass was to be restored and regularly offered alongside the modern mass. Today, priests trained in the modern rite are learning how to celebrate the Latin mass and there is a demand for liturgical resources to accompany it, especially as it follows a different calendar and lectionary. It has an introduction by Mgr Anthony Conlon, Chaplain of the Latin Mass Society, one of a number of societies dedicated to promoting the use of the Extraordinary Rite.