The MOSAIC Consortium held its Science Meeting from October 27 to 29, 2025, at the Venture Studio, located in the Amsterdam Science Park.  More than 60 people attended the meeting in person (see Figure), and over 20 participated online. This meeting aimed to foster interactions within the Science Team and to initiate the preparation of the MOSAIC Red Book, which is expected to be finalized by mid-2027 at the latest. The main objectives were achieved, namely: (i) to inform the team about the project status, science plans, and latest developments in the instrument design; (ii) to encourage interactions and synergies between MOSAIC and other major projects in spectrocopy; and (iii) to discuss new technical and scientific developments that may impact the operation of MOSAIC, in particular for the exploitation of the GTO.