Droplet epitaxy is attracting increasing attention as this technique offers alternative growth potentials for novel configurations of quantum and nanostructures. The back cover article by Jihoon Lee et al. (pp. 348–353) compares self-assembled InGaAs nanostructures grown on GaAs (311)A with the those fabricated on GaAs (100). Under identical growth conditions, the resulting nanostructures are different on the various GaAs surfaces, forming ringshaped structures on GaAs (100) and triangular holed pyramids on GaAs (311)A. The underlying formation mechanism of these interesting nanostructures can be understood in terms of intermixing, dissolution of GaAs substrate and surface diffusion driven by various surface reconstructions.