The plot follows from a murder plot against the heroes' families, and no one is safe, not even Superman's wife, Lois Lane. Someone knows everyone's secret identities and is using that knowledge to perpetrate evil. After a horrific initial death, the heroes hit the streets hard to uncover the mystery threat, but their efforts hit a huge snag. The supervillains, it turns out, after years of being thoroughly romped by their do-gooder counterparts, have organized and are approaching their crimes and attacks in more strategic ways. One of the most controversial parts of the story lies in the heroes' different reactions to these events, and how much they go across their own moral lines in seeking justice. In many ways, their own heroic missions become extremely compromised.
Aside from the treatment of superheroes as morally ambiguous characters, many fans took offense at what they saw as rampant mischaracterizations and plot holes. Additionally, other critics, such as Johanna Draper Carlson and Valerie D'Orazio
The creative team on this story, along with Meltzer, included Rags Morales and Michael Bair, two artists who frequently work collaboratively. Their depictions of the characters are noted for their humanity and emotional expressiveness. They are credited very much in conveying the image of superheroes as regular human beings in extraordinary circumstances. The covers for the series were drawn by fan favorite artist Michael Turner.
Identity Crisis created quite a stir when it was released, and there are a multitude of reviews available online. I include a few here that I think characterize the general discussion: one from Tom Bondurant, one from Collected Editions, and one from Jeff Lester. The story draws very much from earlier stories and DC Comics continuity, and for those interested, here are two links to possible source material, as well as a page of annotations explaining a great number of the characters and situations in chapter 1.