The main points of recent theoretical and computational studies on bou
ndary-layer transition and turbulence are highlighted. The work is bas
ed on high Reynolds numbers and attention is drawn to nonlinear intera
ctions, breakdowns, and scales. The article focuses in particular on t
ruly nonlinear theories for which the mean-flow profile is completely
altered from its original state. There appear to be three such theorie
s, dealing with 1) nonlinear pressure-displacement interactions, 2) vo
rtex/wave interactions, and 3) Euler-scale flows. Specific recent find
ings noted for these three, and in quantitative agreement with experim
ents, are the following. 1) Nonlinear finite-time breakups occur in un
steady interactive boundary layers, leading to sublayer eruption and v
ortex formation; here the theory agrees with experiments on the occurr
ence of the first spike. 2) Vortex/wave interactions give rise to fini
te-distance blowup of displacement thickness, then interaction and bre
akup (as ''in 1''); this theory agrees with experiments on the formati
on of three-dimensional streets. 3) The Euler-scale and related theori
es lead to the prediction of turbulent boundary-layer microscale, disp
lacement- and stress-sublayer thicknesses.