Hi folks, I've searched the archives and boost.org trying to find some help, but I still can't get my head around how the property maps are supposed to work. I'm pretty new to Boost, so I'm maybe not too familiar with the underlying concepts, etc, so forgive me if my question seems a little too basic! My problem is this: Given a directed graph with a single start and end point, I want for each node (vertex) to build a list of all the other nodes that can be reached from the current node. The algorithm is simple, I think: do a depth_first_search() and implement my code on dfs_visitor::finish_vector(). This skeleton I have done. However, the bit I can't get my head around is how to use property maps to collect the info. The key parts of my best effort so far are: struct statement_list_t { typedef boost::vertex_property_tag kind; }; typedef boost::property< statement_list_t, std::set<size_t> > StatementListProperty; typedef boost::adjacency_list< boost::vecS, boost::vecS, boost::bidirectionalS, StatementListProperty, boost::no_property > ADJ_GRAPH; struct connection_detector : public boost::dfs_visitor<> { public: connection_detector() {} template <class Vertex, class Graph> void finish_vertex(Vertex u, const Graph& g) { /* for each child in out_edges( u, g ) current node set = union_of( current, child ) */ } } However, my questions are: 1. std::set<size_t> - is the size_t the best type to store a reference to a vector in? 2. In finish_vertex<> (or other places) how do I address the StatementListProperty value for a given vertex? 3. How would I use an Exterior Property Map instead? Thanks for any advice! Ken