Paths toward understanding black holes

This work can be summarized as trying to understand aspects of black holes, gravity, and geometry, in the context of supergravity and string theory in high-energy theoretical physics.
The two parts of this thesis have been written with entirely different audiences in mind. The first part consists of chapters 1, 2, 3 and is composed of a self-contained laymen's introduction to my research. The second part of this thesis, consisting of chapters 4, 5, 6, 7, 8 contains the main part of this thesis, and is therefore written in a scientific manner. Chapter 4 introduces black holes in general and the various concepts of the subsequent chapters; it also describes how the research presented in those chapters fits into the bigger picture regarding the study of black holes. Following the introductory chapter 4, chapter 5 discusses my research on the concept of exotic branes; chapter 6 deals with my contributions to the study of higher derivatives in gravitational theories; and chapter 7 details my contributions to multi-centered configurations, especially in the context of fuzzballs. Chapter 8 summarizes the main results of the previous three chapters and provides an outlook on possible interesting future directions of research in these subjects.