I'm trying to write this piece of code struct Cell { .... }; typedef boost :: multi_array< Cell, 2 > Grid; void f( Grid & grid ) { for ( Grid::index i=grid.?????(); i!=grid.????(); ++i ) { ..... } } where the intention is to iterate over the first subscript of the multi_array. I can see that index_range has start() and finish() methods, but I can't see how to extract the first index_range from the multi_array. Thanks - Rob.