Klaas had a long and fruitful scientific career with many contributions to science, education, and mentoring. His approach and vision are best characterized as uniquely tolerant, with a focus on the development of new Magnetic Resonance Imaging and Spectroscopy techniques to better understand disease processes. He was very passionate in mentoring his students and he trained some of the currently leading scientists in the experimental MRI field. Klaas was internationally recognized and appreciated for his work and served our community as a member and chairman of various advisory boards. Klaas was a very modest person, but those close to him know how proud he was of his team’s individual members and the appreciation they received for their work on many occasions.