Picasso, Matisse, Miró and Dalí suggest that great works of art continue to command great prices in changing markets

Reasonable results, with collectors looking lively

Fears are growing that the version in the St Petersburg is a replica

Bequest of modern paintings and sculpture to tour American cities

The auction houses bring out six long-held major estates to tempt collectors

A collection of works donated to the nation by Etienne Moreau-Nélaton on display at the Grand Palais

Artists’ techniques revealed through science