Summer is icumen in: Classical concerts fill Ravinia Festival stages, alfresco and indoors

Preview: A bountiful smorgasbord of classical music enriches the summer fare at the 2017 Ravinia Festival. The Chicago Symphony Orchestra puts in a stint with an array of guest conductors and soloists at the festival pavilion, while on a smaller scale indoor venues will see a parade of string quartets and pianists. We offer a comprehensive look-ahead at Ravinia’s classical presentation.