The first TL materials (LiF:Cu,Ag and CaF₂:Mn) and a simple reader were developed in 1966. In the next year methods of production of LiF:Mg,Ti phosphor and sintered pellets, called MTS-N or MTS-7 (1968) and of LiF:Mg,Cu,P (1979) pellets (MCP-N, MCP-7) were developed. The properties of these materials were comprehensively investigated. In investigations of properties of MCP's particular attention was paid to optimisation of the concentration of activators for obtaining the best dosimetry properties and to non typical response of this phosphor to radiation of different LET. For measurements of doses of weakly penetrating ionizing radiation and neutrons the original methods of producing thin dosemeters of different construction were developed. Simultaneously to detector developments more and more versatile readers were constructed as well of manual as of automatic operation. TL method of dose measurements was currently applied in different fields of radiation protection and radiotherapy. In 1968 MTS-7 dosemeters replaced films in routine monitoring of individual doses of the INP workers. This system modernised continuously has been used till now. Levels of natural gamma radiation throughout Poland outdoors and indoors and in more details on several smaller areas were investigated during many years. Measurements of dose rate of gamma radiation on the area of the Institute allowed for observing seansonal dose rate fluctuations and registering coasre and subtle changes after the Chernobyl catastrophe. A method of measurement of radon daughters with the use of thin CaSO₄:Dy pellets was developed and has been used routinely in Polish coal mines. LiF:Mg,Ti detectors with enhanced Li-6 and Li-7 content have been used in an ALBEDO neutron dosimetry system which completed monitoring of the INP workers.