Hello Tiago and everyone, I'd like to bring your attention to a question on stackoverflow, which I'd also like to know the answer to: http://stackoverflow.com/questions/9526827/graph-tool-how-to-access-properti... In particular, this bit: "How do I get an object [vertex] with a certain title back from the graph ? One way seems to be to create a vertex filter using graph.set_edge_filter(...) and apply that - which seems a pretty expensive operation considering all I want is to get one single object back. I really don't want to maintain my own object title / vertex index mapping as IMO, that is one of the tasks of the graph". Consider, for example, the following simple situation: I've got an existing set of vertices and then obtain information on edges between them from somewhere, which may sometimes also involve vertices not yet in the graph. In networkx, I would simply do: add_edge(x,y), where x and y are vertex names (that have or have not been defined a priori using add_node(x)). Is there a straightforward way to do the same in graph_tool? Thanks, Mikhail