Last time I checked "Lisa Meitner: A Life in Physics" is still the best biography on Meitner. Naturally though the fact that she (together with Frisch) worked out a successful theory for nuclear fission to explain Hahn's experimental results is her major scientific accomplishment. That she did not receive a Nobel prize alongside Hahn seems ridiculous when judged solely on her scientific contributions. I will note though that her being snubbed for a Nobel probably shouldn't be attributed entirely to sexism, the committee's well documented preference for experimental contributions over theoretical likely played a part as well.