In 2004 and again in 2010, Along the Web explored the topic of volunteers in arts, heritage and culture. In this issue, we revisit that sector to look at volunteers’ input that relates specifically to public library services. Whether funded by governments, philanthropists, donors or private subscription, libraries are universal and one of the most egalitarian of services in their reach and access. But surprisingly, the extent of involvement of volunteers in library services varies widely, from a great deal to very little at all. In this article, Arnie Wickens explores how trying to discover the real impact volunteers make on library services – beyond just the numbers of people involved, what they do, or the hours that they give – is almost impossible.