Tobias Mühlenbruch is a private lecturer at the FernUniversität in Hagen, Germany. His main research interest include number theory with a focus on analytic modular forms and the connections to dynamical systems and mathematical physics. 

Wissam Raji is an Associate Professor of Mathematics at the American University of Beirut, Lebanon. His research interests include analytic number theory and modular forms with a focus on period polynomials. He is the recipient of numerous awards, including the Saylor Foundation's 2013 Open Textbook Challenge.

1. A Brief Introduction to Modular Forms.- 2. Period Polynomials.- 3. Maass Wave Forms of Real Weight.- 4. Families of Maass Cusp Forms, L-Series and Eichler Integrals.- 5. Period Functions.- 6. Continued Fractions and the Transfer Operator Approach.- 7. Weak Harmonic Maass Wave Forms.- A. Background Material.- References.- Symbol Index.- Index.