The textbook "Investigation of Deep Trap Levels in Semiconductor Structures Using PICTS and PL Methods" by Hatice Basak offers a comprehensive examination of deep trap levels in semiconductor materials, particularly in GaInNAs/GaAs doped quantum structures. The analysis is conducted using Photo-Induced Current Transient Spectroscopy (PICTS), which allows for the determination of activation energies and capture cross-sections of the deep levels. The book addresses both simple and multiple quantum wells and explores the effects of thermal treatments on the electrical properties of these materials. The results are discussed in the context of existing literature, providing the reader with deep insights into the current developments and challenges in semiconductor research.