Editorial: Honoring Prof. Age K. Smilde

It is both a privilege and an emotional moment for me to write this editorial for the special issue of the Journal of Chemometrics honoring Prof. Age K. Smilde, who recently retired. For me, and for countless others in our field, Prof. Smilde (also more informally know as Age) has been more than a scholar; he has been a mentor, a collaborator, and an inspiration whose contributions have left a huge mark on the world of chemometrics.

Looking back, it feels almost surreal to think of my early days in academia, 30 years ago, when I was navigating the complex world of multi-way tensor analysis. At the time, Age seemed to me to be the quintessential ‘all-knowing’ professor. His mastery of the field, combined with a willingness to mentor and nurture young scientists, made a profound difference in my career. I remember a conference where he explained the complexity of tensor rank. I quickly grasped the problem and slightly arrogantly said: I will fix it. I tried. I was very fast and 100% wrong. I never managed to make even the slightest progress!

He played a pivotal role in helping me craft some of my earliest papers, including one of the first approaches to tensor regression. Our discussions on the properties of multi-way arrays and their applications remain etched in my memory—not just as lessons in science, but as moments of shared curiosity.

Age's career is nothing short of extraordinary. From his foundational work at the University of Groningen to his tenure at the University of Amsterdam, where he led the group later known as Biosystems Data Analysis, Age has consistently been at the forefront of methodological advancements in not just chemometrics. His work on multi-way analysis, data integration, and systems biology has truly shaped the respective fields. It is no surprise that he has been honored with numerous awards, such as the prestigious Herman Wold Gold Medal and the Kowalski Award, reflecting his pioneering contributions and global recognition.

What sets Age apart, is his ability to foster collaboration and build bridges within the scientific community. He introduced me to some of the most significant researchers not only in chemometrics but also in psychometrics, widening my horizons and opening doors that would otherwise have remained closed. His efforts to create platforms for collaboration, such as co-founding TRICAP and contributing to international chemometric meetings, have enriched our discipline.

Reflecting on the arc of our careers, I cannot help but smile at the realization that the ‘old’ professor who once seemed so far ahead of me is, in fact, only a few years my senior. Time has a way of leveling us, and today I count Age as not only a colleague but also a dear friend and peer. His wisdom, humility, and warmth continue to inspire, and his legacy will undoubtedly endure through the countless students, collaborators, and researchers he has influenced.

This special issue is a testament to Prof. Smilde's impact on our field. It brings together contributions from researchers whose work has been shaped by his ideas, mentorship, and collaborations. It is a fitting tribute to a scientist like Age.

On behalf of all who have had the privilege of working with Prof. Smilde, thank you, Age, for your tireless contributions, your mentorship, and your friendship. We celebrate not just your remarkable career but also the person behind it—a true giant of chemometrics.