This lecture discusses the concept of improper integrals, focusing on their definitions and properties in two and three dimensions. The instructor explains the challenges of working with infinities in R2 and R3 compared to R. The lecture covers the construction of improper integrals, emphasizing the importance of integrable functions and bounded hypotheses. Various examples are provided, illustrating how to calculate integrals over specific regions and the significance of absolute integrability. The instructor highlights the necessity of verifying hypotheses to ensure convergence and avoid contradictions. The lecture concludes with a discussion on the implications of absolute integrability and its role in determining the convergence of integrals, particularly when dealing with functions that can change signs. Overall, the lecture provides a comprehensive overview of improper integrals, their applications, and the mathematical rigor required in their analysis.