See this online text:

  • “The Eucharist: Source and Summit of the Life and Mission of the Church”, Lineamenta by the Tenth Ordinary General Assembly of the Synod of Bishops General Secretariat, 25 February 2004. May be read online at the Holy See.

See also the texts under sub-list IV “On the Blessed Eucharist and the Sacrifice of the Mass” on the page Sacraments, and under sub-list III.B “About the Holy Sacrifice of the Mass” on the page Liturgy; as well as:

On the Feast of the Most Holy Body of Christ (Corpus Christi) in the Latin Church (Roman Rite). For other texts and ebooks, you may access the List of Free eBooks (Arranged by Title), the List of Free eBooks (Grouped by Subject), the List of Worth-It Catholic Books & eBooks, and the main page of the Catholic eBooks Project.