The Ecumenical Councils of the Roman Catholic Church
A list of summaries of the main facts of each recognised council.

The Church in Crisis A History of the General Councils - AD 325 through AD 1870
Text of the 1960 book by Monsignor Philip Hughes giving an historical background and an account of the proceedings of all the main Catholic ecumenical councils until Vatican I.

General Councils
Article from the Catholic Encyclopedia, looking at the definition, place in church governance and short historical sketches of each council until Vatican I.