Tremolo is a spectral library search tool that leverages the Spectral Library Generating Function (SLGF) concept to identify spectrum-spectrum matches (SSMs). The SLGF models the variability of replicate spectra as compared to reference library spectra. Given a similarity function (in our case cosine), SLGF yields an expected score distribution for each reference library spectrum. Tremolo is able to assign p-values to SSMs and it has been shown to increase the sensitivity of spectral library searches.