The paper describes the research on soft X-ray lasers with an active medium created using a gas puff target irradiated

with high-intensity laser pulses. The gas puff target in a form of an elongated gas sheet is produced by pulsed injection of

gas through a slit nozzle using a high-pressure electromagnetic valve. The method of generation of soft X-ray lasers using a

laser-irradiated gas puff target has been developed at the Institute of Optoelectronics. The collaborative experiments were

performed at various laser laboratories using high-intensity laser systems to irradiate the gas puff target and pump the X-ray

laser active medium. Results of these experiments are presented and discussed. Works aimed at increasing the efficiency of

X-ray lasers using a longitudinally irradiated gas puff target are also reviewed.