Explore the concept of spectrum in hypersurface singularities through this comprehensive lecture by Josef Svoboda from the University of Miami/IMSA. Begin with examples of singularities and their spectra, followed by an overview of the spectrum's definition. Delve into crucial properties such as the Thom-Sebastiani theorem and semicontinuity, understanding their significance in practical applications. Conclude by examining computational techniques for obtaining the spectrum. Topics covered include the Milner Fiber, Geometric Monodromy, Link, Mixer Structure, and Global Applications, providing a thorough understanding of this powerful invariant originally defined by Arnold, Varchenko, and Steenbrink.