This lecture provides an introduction to transmission line effects in the time domain. Fundamentals including time of flight, impedance discontinuities, proper termination schemes, nonlinear and reactive loads, and crosstalk are considered. Required prerequisite knowledge is limited to conventional circuit theory. The material is intended to supplement standard textbooks for use with undergraduate students in electrical engineering or computer engineering. The contents should also be of value to practicing engineers with interests in signal integrity and high-speed digital design.