MATRIX is Australia's residential mathematical research institute. It facilitates new collaborations and mathematical advances through intensive residential research programs, each 1-2 weeks in duration. This book is a scientific record of the 14 research programs held at MATRIX in 2023, including combined events with the Mathematisches Forschungsinstitut Oberwolfach (MFO), and with the Research Institute for Mathematical Sciences Kyoto University (RIMS).