Linear series on smooth curves parametrize invertible sheaves together with linear subspaces of their global sections. This has been generalized to nodal curve of compact type by Eisebud-Harris and Ossermann. I will present an approach to the problem using logarithmic geometry which allows us to extend the theory of linear series to arbitrary nodal curves. A prominent role is played by vector bundles on Olsson fans, which I will introduce. This is joint work in progress with Luca Battistella and Jonathan Wise.