Since the turn of the century, geology has advanced dramatically, with materials derived from extra-terrestrial sources meaning that it now encompasses cosmology, and new technologies providing ever more sophisticated possibilities for the conducting of research. This book, Unconventional Methods for Geoscience, Shale Gas and Petroleum in the 21st Century, aims to provide research directions for geology in the 21st century. As Eric Hobsbawm wrote, it is difficult to write the history of one's own days, and selecting influential methods was no easy task, but an attempt has been made to include the most influential papers that represent the smart geology of the first few decades of the 21st century. The book presents 22 papers; the first serves as an introduction to biology, which is now expanding into the science of the cosmos following the discovery of previously missing information, and the remaining 21 papers are divided into 3 sections entitled Modelling, Simulation and Optimization. The importance of theoretical approaches from physics, mathematics, and statistics underlying meta-heuristic methods, knowledge and approaches is acknowledged, and there is a chapter dedicated to deep learning. The book contributes to the exploration of various possible solutions to challenging problems in both the Earth's geology and that of the cosmos, and will be of interest to all those working in the field. © 2023 The authors. All rights reserved.