This invaluable book provides a comprehensive treatment of the design and application of Mode Locked Lasers and Short Pulse Generation. With the advances in semiconductor laser and fiber laser technologies in the 1980s to now, these devices have been made compact, refined, and developed for a wide range of applications including further scientific studies. Semiconductor mode-locked lasers are stable pulse sources and can be made over a range of wavelengths where laser operation is feasible. Rare earth doped fiber lasers or planar waveguides extend this range further and can provide compact pulsed sources. The principles of operation, analysis, design and fabrication of these sources are described. Recent results on high repetition rate and high-power pulse generation from these compacts sources are also described, together with current and future directions of application of these types of laser sources. Mode-Locked Lasers: Introduction to Ultrafast Semiconductor and Fiber Lasers is self-contained and unified in presentation. It can be used as an advanced text by graduate students and by practicing engineers. It is also suitable for non-experts who wish to have an overview of mode-locked lasers and pulse generation. The explanations in the book are detailed enough to capture the interest of the curious reader and complete enough to provide the necessary background to explore the subject further.