Explore the characteristics, origins, and evolution of multiplicity in protostellar systems in this 33-minute conference talk by John Tobin from the National Radio Astronomy Observatory. Delivered at the Building Bridges: Towards a Unified Picture of Stellar and Black Hole Binary Accretion and Evolution Conference at the Kavli Institute for Theoretical Physics, delve into topics such as multiple star formation, protostellar multiplicity, and disk fragmentation. Examine evidence from VLA and ALMA observations of nascent disks in the Western Perseus Molecular Cloud and the VANDAM Orion sample. Investigate the multiplicity and companion frequency of intermediate-mass protostars, separation distribution, and the origins and evolution of multiplicity. Gain insights into evidence for disk fragmentation and migration in protostellar systems, concluding with a comprehensive summary of the latest findings in this field of astrophysics.