Who is an apostle? While the New Testament seems to only include Paul with the Twelve, many passages expand the meaning. It is that expanded meaning that Phyllis Zagano uses to name twelve apostles from the twentieth century, with the hope that by examining their lives others will be encouraged to live similarly.

In Twentieth-Century Apostles, Zagano explains that many apostles never received their commission directly from Jesus in the flesh, but were both called and sent by the living Jesus in their souls. Like Paul, they never claimed to be apostles, but their right to be known as such is based on their living the common characteristics of an apostle: personal election by Jesus and personal experience of the living Jesus, in life (as with the Twelve) or in the resurrection (as with Paul). They proclaim the risen Lord and carry on the tradition. They are the basic constitutive elements of the Church.

Zagano selects twelve apostles from the twentieth century whose lives and writings portray both their deep relationship with God and their intense involvement with the world around them. In Twentieth-Century Apostles she examines those lives and writings by devoting a chapter to each of the twelve apostles she has selected Charles de Foucald, Pierre Teilhard de Chardin, Giovanni Battista Montini (Pal VI), Dorothy Day, Jessica Powers, Franz Jägerstätter, Teresa of Calcutta, Thomas Merton, Roger of Taiz é, Oscar Romero, Jean Vanier, and Thea Bowman.

The apostles in Twentieth-Century Apostles span this century, as historical records of our progress and as predictors of times to come. Called and sent, they lead us all in lives of prayer and service.