Addressing both physical and mathematical aspects, this self-contained text on boundary value problems is geared toward advanced undergraduates and graduate students in mathematics. Prerequisites include some familiarity with multidimensional calculus and ordinary differential equations. Problem sets appear throughout the text, along with a substantial number of answers to selected problems. Includes a new Introduction, updated appendixes, and corrections. AUTHOR: John L. Troutman is Professor Emeritus of Mathematics, Syracuse University. Maurino Bautista is Professor of Mathematics, Rochester Instititue of Technology.