This was by no means a pleasant or easy book to read, but it was extremely well-written and well-researched, and while the author does engage in a lot of speculation as to what the three main players in the crime might have thought or felt, nothing she proposes seems very far from the truth.
Some have complained that Johnson wanted to bring down Hedda Nussbaum right from the start, and she may have, but I also believe she was willing to give the woman a fair shot, and ultimately it's Hedda's own words and actions that shatter the carefully-cultivated image of her as a saintly, helpless victim, an image cultivated not so much by Hedda herself but by the many well-meaning advocates and activists who elevated her to tragic-heroine status.
Hedda reminds me very much of Karla Homolka, though Joel Steinberg is hardly Paul Bernardo. Both Homolka and Nussbaum were indisputably abused, but they were just as clearly active, even enthusiastic, participants in the abuse of others, and both were willing to play up their victim status in order to evade punishment for their crimes. Homolka's true nature surfaced only many years after she had been (lightly) sentenced, due to highly questionable tactics by her lawyers during the trial.
Johnson and others closely involved in the Steinberg case believed (at the time the book was written, 1990) that incriminating videotapes of Nussbaum and Lisa Steinberg are still out there somewhere. So far none have surfaced, but Nussbaum herself dropped hints, and other people associated with her and Joel Steinberg have mentioned them, and others were implicated but never charged with molesting Lisa.
Nussbaum has of course written her own memoir, many years after "What Lisa Knew" was published, but she has never truly accepted responsibility for Lisa's death. Throughout her life, even long before she met Steinberg, she was prone to angry outbursts, self-centeredness and a nearly blank personality that she molded to match the expectations of whoever happened to be paying her attention at the moment. This comes through loud and clear in Johnson's narrative and in the many interviews with friends and relatives of everyone involved.
The most disturbing aspect of the whole case is not even what happened to Lisa, though that's certainly terible enough; rather, it's the fact that many, many different people, at every point in her life, knew that there was something badly wrong in the household, and yet very few even attempted to do anything about it. Those few who did try to get help for Lisa were unsuccessful, yet they end up lumped together with those who chose to do nothing at all. And yet most of these passive observers were not evil or even immoral people. They were completely ordinary people like most of us want to believe ourselves to be.