Dorian Garrick has made major research contributions to the theory and application of genetic evaluation for animal breeding. The challenge for informed selection is to obtain the best possible evaluation of a selection candidate’s merit, using all the available information. Combining all available information into optimal and fully commensurate evaluations (“predictions”) of genetic merit or future performance is extremely complex and demanding. Garrick has substantially refined both the algorithms and the formidable calculations involved as available information on selection candidates has increased prodigiously in recent years, with enhanced data logging and an explosion of genomic information. His work is remarkable not just for fundamental contributions to methodology but also for its national and international implementations, across a range of animal species: sheep, beef cattle, dairy cattle, pigs, poultry, and occasionally deer, horses and dogs. He has also engaged significantly with quantitative issues of plant improvement.