Linear Algebra and its Applications 373 (2003) 1–3 www.elsevier.com/locate/laa Preface Special Issue on the Combinatorial Matrix Theory Conference It is our pleasure to present this special issue of Linear Algebra and its Applica- tions devoted to Combinatorial Matrix Theory. The essence of Combinatorial Matrix Theory (CMT) is to use graph theoretic and combinatorial tools to better understand properties of matrices, and to use analytic, geometric and algebraic tools developed for matrices to solve combinatorial problems. This essence was already present in the elegant work of Cayley [2], Frobenius [3], and König [4]. Over the past four decades, CMT has developed into a vital area of mathematical research. The main catalysts for this development are the pertinence and utility of the subject to new applications, Ryser’s 1963 monograph [5], which laid the foundation for CMT, and the 1991 book of Brualdi and Ryser [1], which properly framed CMT and presented blueprints for future research. This special issue arose in conjuction with the Combinatorial Matrix Theory Conference held January 14–17, 2002 at Pohang University of Science and Techno- logy in South Korea. The conference attracted over 60 participants from 15 different countries. The wealth and promise of CMT is reflected by the wide-range of topics (including algebraic graph theory, enumeration of (0, 1)-matrices, permanents and rook polynomials, orthogonal and Hadamard matrices, qualitative matrix theory, linear preservers, digraphs, and matrix completion problems) that were discussed at the meeting. The invited speakers were: Richard Brualdi, University of Wisconsin-Madison, USA Miroslav Fiedler, Czechloslovakia Academy of Sciences, Czech Republic Willem Haemers, Tilburg University, Netherlands Charles Johnson, College of William and Mary, USA Steve Kirkland, University of Regina, Canada Arnold Kräuter, University of Leoben, Austria Qiao Li, Shanghai Jiao Tong University, China Zhongshan Li, Georgia State University, USA 0024-3795/$ - see front matter  2003 Elsevier Inc. All rights reserved. doi:10.1016/S0024-3795(03)00583-4