The lecture will begin with a very brief history of the development of nylon 4 from its initial discovery to the present-day polymer where polymerization times have been reduced from the original 7 days to 3 hours and the thermal stability of the polymer improved to the point where melt spinning in an extruder is possible. Polybutyrolactam (nylon 4) is basically a thermally unstable material and when melted it will revert to its thermodynamically stable 5-membered ring monomer. With properly prepared polymer however this process takes enough time to permit commercial melt spinning when a screw of optimized design is used in combination with a proper temperature profile and reduced dwell time. Certain properties of the polymer which relate to its melt spinning will be discussed, e.g. molecular weight and molecular weight distribution (GPC), melt viscosity and shear as well as thermal characteristics (TGA and DSC). Some of the properties of the fiber will be mentioned primarily from the point of view of why it is worthwhile to learn how to make this fiber commercially.