This book provides a concise introduction to practical aspects of atomic-resolution imaging in aberration-corrected electron microscopy. As such, it addresses recent advances in electron optical instrumentation used for ultra-high resolution imaging in materials and nano-science. It covers two of the most popular atomic resolution imaging techniques' namely high-resolution transmission electron microscopy and scanning transmission electron microscopy. The book bridges the gap between application-oriented textbooks in conventional electron microscopy and books in physics covering dedicated topics in charged-particle optics and aberration correction.The book is structured in three parts which can be read separately. While in the first part the fundamentals of the imaging techniques and their limits in conventional electron microscopes are explained, the second part provides readers with the basic principles of electron optics and the characteristics of electron lenses. The third part, focusing on aberrations, describes the functionality of aberration correctors and provides readers with practical guidelines for the daily work with aberration-corrected electron microscopes. The book represents a detailed and easy readable guide to aberration-corrected electron microscopy.