The celebrated superfluid properties of helium-4 only exhibit themselves while the liquid is being treated fairly gently. Up to a certain critical velocity it can flow through a tube in a completely frictionless manner, without needing to be pushed to keep it moving. At higher speeds, however, this simple superfluid behaviour disappears abruptly as turbulence is generated and a corresponding flow resistance appears. The resultant turbulent state of the superfluid is of considerable intrinsic interest, particularly in view of the quantum properties of the liquid. A recent paper in Physical Review Letters (38, 551; 1977) by K. W. Schwarz of the IBM Research Centre at Yorktown Heights represents the first serious attempt to tackle the dynamics of the turbulence and, judging by comparisons with experimental data, his theory seems to be remarkahly successful.