Recent developments in the “omics-“ sciences allow evolutionary biologists to address the drivers of adaptation and speciation, i.e. the origin and maintenance of biological diversity, in increasingly rigorous and less naïve ways. My group’s research interests revolve around the use of novel laboratory and computational tools for studying adaptation, speciation, and species radiations in plants. In my talk, I will highlight recent progress of our work. This will include whole-genome perspectives on eco-evolutionary processes in the ´model forest tree´ Populus both at the early stages of speciation, such as adaptive introgression, and previously underexplored phenomena readily observable at late stages of speciation, such as the genomic architecture of fitness-related trait differences, genomic co-adaptation, heterosis, and hybrid breakdown. I will highlight some of the current gaps in our understanding of speciation and species radiations, e.g. regarding the mechanisms at work during the late / advanced stages of speciation, and conceptual gaps between research targeting micro-evolutionary time scales (population genomics) and macro-evolutionary time scales (phylogenomics). These gaps are currently being closed at a rapid pace. I will sketch some recent progress towards this goal, speaking primarily from a plant evolutionary biologist´s perspective.