As data volumes surge, deep learning is becoming increasingly important in particle physics. This special edition on artificial intelligence (AI) captures two new trends: using “unsupervised” deep learning to spot anomalous events, and designing AI that can “think not link”. Community-organised data challenges are leading the way and deep learning could even be used in the level-one triggers of LHC experiments. To keep up with the cutting edge of AI research, physicists are reaching out to computer science and industry: the latest developments could help explore theory space and build trust in AI to do more of the heavy lifting throughout the analysis chain. We also explore recent thinking that an ordered simplicity may emerge from the complexity of deep learning in a similar way to statistical mechanics and quantum field theory. Elsewhere in the issue: a tribute to Steven Weinberg; a SciFi upgrade for LHCb; reports from the summer conferences; the most stable tetraquark yet; quantum gravity in the Vatican; anisotropies point to cosmic-ray origins; and much more.