Diomidis Spinellis is a Professor in the Department of Management Science and Technology at the Athens University of Economics and Business, Greece. His research interests include software engineering, programming languages, IT security, big-data processing, and optimization methods. He holds an MEng in Software Engineering and a PhD in Computer Science both from Imperial College London.

Spinellis has published two books in Addison-Wesley's "Effective Programming Series": in 2004 Code Reading: the Open Source Perspective, which received a Software Development Productivity Award in 2004 and has been translated into six other languages, and in 2006 Code Quality: the Open Source Perspective, which also received a Software Development Productivity Award in 2007. Both books use hundreds of examples from large open source systems, like the BSD Unix operating system, the Apache Web server, and the HSQLDB Java database engine, to demonstrate how developers can comprehend, maintain, and evaluate existing software code. Spinellis has published more than 300 technical papers in journals and refereed conference proceedings, which have received more than 8000 citations. He served for a decade as a member of the IEEE Software editorial board, authoring the regular “Tools of the Trade” column, and as the magazine's Editor-in-Chief over the period 2015–2018. He has also contributed a chapter to the best-selling book Beautiful Code: Leading Programmers Explain How They Think (O'Reilly, 2007).

Spinellis is the author of many open-source software packages, libraries, and tools and has contributed to the FreeBSD operating system as a committer (2003-2010). His implementation of the Unix sed stream editor is part of all BSD Unix distributions and Apple's macOS. Other tools he has developed include the UMLGraph declarative UML drawing engine, the CScout refactoring browser for C programs, the sgsh scatter gather shell that constructs directed graph process pipelines, the ckjm tool for calculating Chidamber and Kemerer object-oriented metrics in large Java programs, the Outwit suite for integrating Windows features with command-line tools, the fileprune backup file management facility, and the socketpipe network plumbing utility. Dr. Spinellis serves as an elected member of the IEEE Computer Society Board of Governors (2013-2015), and is a senior member of the ACM and the IEEE, and a member of the Usenix association. He is four times winner of the International Obfuscated C Code Contest and a member of the crew listed in the Usenix Association 1993 Lifetime Achievement Award.