Mepụta ụdị okwu a dị mgbagwoju anya nke ahịrịokwu a Na Twinkling nke Anya / Countdown to Earth's Last Days dị ka akwụkwọ akụkọ nke atọ na usoro Left Behind.
N'ezie, ụdị okwu dị mgbagwoju anya nke ahịrịokwu ahụ bụ "N'otu ntabi anya / Countdown to the Earth's Last Days bụ akwụkwọ akụkọ nke atọ na usoro Left Behind, nke Tim LaHaye na Jerry B. Jenkins dere na 2006. "