I've only read a few books by Oscar Cullmann, and while they are not astounding I think that they are only not because much of what he was about has become mainstream - in conservative evangelicalism at least. Wikipedia describes him so:
Oscar Cullmann (25 February 1902, Strasbourg - 16 January 1999, Chamonix) was a Christian theologian in the Lutheran tradition. He is best known for his work in the ecumenical movement, being in part responsible for the establishment of dialogue between the Lutheran and Roman Catholic traditions. Because of his intense ecumenical work, Cullmann's Basel colleague Karl Barth joked with him that his tombstone would bear the inscription "advisor to three popes."
Within the evangelical tradition he is remembered slightly differently as the author of the (good) cliché that Christ's death and Resurrection can be compared with D-day as the decisive battle in a war that rumbles on although VE-day, when sin and death are completely destroyed, is yet to come. I think this comes closer to the heart of what he was about (not that I have any authority to say so). He says of his important work Christ and Time:
The whole of early Christian thought is based in Heilsgeschichte [salvation history], and everything that is said about death and eternal life stands or falls with a belief in a real occurrence, in real events which took place in time. [...] The purpose of my book Christ and Time was precisely to show that this belongs to the substance, to the essence of the early Christian faith, that it is something not to be surrendered, not to be altered in meaning;