Book excerpt: Advances in High-Power Fiber and Diode Laser Engineering provides an overview of recent research trends in fiber and diode lasers and laser systems engineering. In recent years, many new fiber designs and fiber laser system strategies have emerged, targeting the mitigation of different problems which occur when standard optical fibers are used for making high-power lasers. Simultaneously, a lot of attention has been put to increasing the brightness and the output power of laser diodes. Both of these major laser development directions continue to advance at a rapid pace with the sole purpose of achieving higher power while having excellent beam quality.