Dari Cornelius Platinga, Jr., pemenang penghargaan Book of the Year Christianity Today pada tahun 1996, lahirlah buku berisi renungan-renungan dengan perhatian-perhatian theologis yang begitu erat dikaitkan dengan keseharian hidup orang Kristen. Jaminan Iman mebukakan kebenaran-kebenaran iman Kristen yang mendalam dengan mengajukan pertanyaan-pertanyaan dasar.
Cornelius Plantinga, Jr. is an ordained minister in the Christian Reformed Church and has served as a pastor in Webster, NY and supply preacher in Cliffwood Beach, NJ. Before joining the faculty at Calvin Theological Seminary, Cornelius Plantinga Jr. taught at Princeton Theological Seminary (1976 - 78), Fuller Theological Seminary (1985, 1987) and Regent College (1997). From 1996 to 2002 he served as the first ever Dean of the Chapel at Calvin College. He now serves as President of the seminary and teaches systematic theology.