The development of new materials of natural origin and biodegradable characteristics for many applications is one of the most important challenges for the materials research groups and polymer industry during the next few years. Poly(lactic acid), PLA, is a biodegradable polymer synthesised from lactic acid (LA), which on its side is obtained from renewable resources. The editors have carried out a selection and seemingly have chosen enough of good reviews and unique works in the branch of lactic acid and its properties, polymerisation and final applications of PLA. Apparently, these works are at the front edge of science and will be of interest for high readership of scientists and students in the branch of chemistry and physics of polymers and biopolymers. The editors expect that the readers will be happy with this selection.