Fritz Gesztesy, Baylor University, Waco, TX, Roger Nichols, The University of Tennessee at Chattanooga, TN, and Maxim Zinchenko, University of New Mexico, Albuquerque, NM.

• IntroductionA bit of physical motivationPreliminaries on ODEsThe regular problem on a compact interval $[a,b]\subset\mathbb{R}$The singular problem on $(a,b)\subseteq \mathbb{R}$The spectral function for a problem with a regular endpointThe 2 x 2 spectral matrix function in the presence of two singular interval endpoints for the problem on $(a,b)\subseteq\mathbb{R}$Classical oscillation theory, principal solutions, and nonprinicpal solutionsRenormalized oscillation theoryPerturbative oscillation criteria and perturbative Hardy-type inequalitiesBoundary data mapsSpectral zeta functions and computing traces and determinants for Sturm-Liouville operatorsThe singular problem on $(a,b)\subseteq\mathbb{R}$ revisitedFour-coefficient Sturm-Liouville operators and distributional potential coefficientsEpilogue: Applications to some partial differnetial equations of mathematical physicsBasic facts on linear operatorsBasics of spectral theoryClasses of bounded linear operatorsExtensions of symmetric operatorsElements of sesquilinear formsBasics of Nevanlinna-Herglotz functionsBessel functions in a nutshellBibliographyAuthor indexList of symbolsSubject index