The growth of technology for chemical assessment has led to great developments in the investigation of chemical reactivity in recent years, but key information is often dispersed across many different research fields. Combining both original principles and the cutting-edge theories used in chemical reactivity analysis, Chemical Reactivity, Volume 1 present the latest developments in theoretical chemistry and its application for the assessment of chemical processes. Beginning with an exploration of different theories and principles relating to electronic structure and reactivity of confined electronic systems, the book goes on to highlight key information on such topics as Dyson orbitals, target-ion overlaps, reaction fragility, magnetizability principles and the Fuki function. Density Functional Theory is discussed in relation to numerous different principles and approaches, with further information on constrained methods and diabatic models, bonding evolution theory, orbital-based population analysis models and charge transfer models, and Quantum chemistry and QTAIM. Consolidating the knowledge of a global team of experts in the field, Chemical Reactivity, Volume 1: Theories and Principles is a useful resource for both students and researchers interested in gaining greater understanding of the principles and theories underpinning chemical reactivity analysis. © 2023 Elsevier Inc. All rights reserved.