Tandem mass spectrometry has emerged to be one of the most powerful techniques for proteomics study. We aimed to improve existing algorithms and develop new algorithms for proteomic mass spectrometry data analysis. Three studies were presented in this book. (1) De novo peptide sequencing via tandem mass spectrometry is of interest in various situations. We developed a dynamic-programming-based suboptimal algorithm for de novo peptide sequencing. (2) A major known problem for protein and peptide identification using mass spectrometry database search is that the speed of database search is too...