A view is a sequence adaptor delivering an altered presentation of one or more underlying sequences. Views are lazy, meaning that their elements are only computed on demand. Similarly to the short-circuit |logical operations| and |eval_if|, views make it possible to avoid premature errors and inefficiencies from computations whose results will never be used. When approached with views in mind, many algorithmic problems can be solved in a simpler, more conceptually precise, more expressive way.