Understanding the interaction between electromagnetic radiation and matter is crucial for unravelling the internal structure and processes of materials. Electromagnetic waves exhibit both wave-like and particle-like behaviour, with the quantized nature of light becoming apparent in the realm of quantum technologies. The QU-ATTO network aims to merge the fields of quantum optics and quantum information science with attosecond physics. This involves focusing on experimental campaigns to highlight quantum aspects in the interaction of intense laser fields with matter and advancing theoretical descriptions for a comprehensive understanding of the quantum state of light associated with intense laser fields. Traditionally, attosecond pulses have been generated using table-top femtosecond lasers. However, recent experiments performed at free-electron lasers (FELs) have demonstrated the production of isolated attosecond pulses and precise control of attosecond waveforms for pulse trains, leading to remarkable advancements in attosecond science. The network also aims to leverage recent advances in seeded FELs and high-intensity high-harmonic generation (HHG)-based attosecond sources to demonstrate the coherent control of electronic dynamics in systems of increasing complexity. The QU-ATTO network represents a comprehensive effort to advance the understanding and control of the interaction between electromagnetic radiation and matter, with a specific focus on merging quantum optics, quantum information science, attosecond physics, and free-electron laser science. The doctoral candidates (DCs) in the network will receive multifaceted scientific training encompassing experimental and theoretical aspects of quantum information science, strong-field physics, and soft X-ray and X-ray science, as well as extensive training in transferable skills and self-management techniques.