A. F. Shields carried out his doctoral research study on sediment transport in the Technischen Hochschule Berlin. He is well known for proposing a useful diagram, known as Shields diagram, that provides the criterion for the threshold of sediment entrainment, which is an essential requirement for the determination of sediment motion in a loose boundary stream. His diagram becomes famous and is most frequently referred in the literature. It has provided an enormous inspiration to initiate a sizable number of researches over last seven decades. Since his pioneering work, numerous attempts have so far been made to quantify the required flow condition (threshold boundary shear stress) for the beginning of sediment movement. The important laboratory experimental and theoretical studies on threshold of sediment entrainment under steady stream flows are briefly summarized, as a perspective review, highlighting the empirical formulations and semitheoretical analyses. A special attention is given towards the influence of the turbulent bursting on sediment entrainment. Latest experiments evidence the mechanism of sediment entrainment is governed by the sweep events. © Springer-Verlag Berlin Heidelberg 2011.