This dissertation describes an extensive account of and advances in sequencing approaches of the mixed-model just-in-time sequencing problem with the goal of keeping the rate of usage of parts as constant as possible. The description of the sequencing approaches is helpful since it gives a thorough and easily readable overview of the existing literature. It contains numerous new results, which have been accepted in international journals, as well. The multi-level case of the problem is NP-hard. However, the single-level case (with significant or negligible change-over time and arbitrary or unit processing time) is polynomially solvable depending on the size of the instance. The dissertation describes several heuristics also. It contains the discussion of some related problems. Moreover, a number of unsolved problems have been given for future research.