Hi All I'm still plugging away at trying to make use of multi_array, but I seem to be having a few problems! I suspect my understanding of the basic paradigm is flawed. I'm bit confused about views and slices. If I start with a rectangular, 2 dimensional grid, take a view of the whole grid, and then use a single subscript to index into that view, then I expected the result to be a view of one less dimension then the original view. However, it seems to be a "sub_array". #include "boost/multi_array.hpp" struct Cell { int i; }; int main( ) { typedef boost :: multi_array_types :: index_range range; boost :: multi_array< Cell, 2 > grid( boost :: extents[ 9 ][ 9 ] ); boost :: multi_array< Cell, 2 > :: const_array_view< 2 > :: type const_grid_view = grid[ boost :: indices[ range( ) ][ range( ) ] ]; boost :: multi_array< Cell, 2 > :: const_array_view< 1 > :: type const_row_view = const_grid_view[ 5 ]; return 0; } The error message from the last assignment is this sample.cpp: In function `int main()': sample.cpp:13: error: conversion from `boost::detail::multi_array::const_sub_array<Cell, 1u, const Cell*>' to non-scalar type `boost::detail::multi_array::const_multi_array_view<Cell, 1u, const Cell*>' requested which seems to confirm I've got all my consts and dimensions correct. So, why is this wrong? Also, does the return type of sub_array, rather than array_view, mean that the contents of the relevant cells have been copied? Thanks - Rob.