Reddit mentions of Identity Crisis

• Crisis on Infinite Earths | Marv Wolfman
  
• Identity Crisis | Brad Meltzer
  
• Infinite Crisis | Geoff Johns
  
• 52 | Geoff Johns, et al.
  
• Final Crisis | Grant Morrison
  
• Blackest Night | Geoff Johns
  
• Flashpoint | Geoff Johns
  
• Forever Evil | Geoff Johns
  
• The Multiversity | Grant Morrison
  
• Darkseid War | Geoff Johns
  
• DC Universe: Rebirth | Geoff Johns
  

Hush is often regarded as one of the best Batman trades out there, so you're off to a good start.

Here's a rough list of other books you might enjoy, all widly embraced by fans of Batman while staying with a darker tone similar to Hush.

• Batman: Year One
  
• Batman: The Long Halloween
  
• Batman: Dark Victory
  
• Batman: The Killing Joke
  
• Batman: Haunted Knight
  
• Batman: A Death in the Family
  
• Arkham Asylum
  
• JLA: Tower of Babel
  
  I''d also suggest reading Identity Crisis. Batman isn't the only character of the story, and while he doesn't make many appearances when he does he certainly makes an impact. Lastly, Gotham Central is also a great read, but it focuses on the GCPD MCU rather than on Batman himself, and how they deal with supervillains and working in a city with a masked vigilante.
  
  Hope this helps.

The title says that he's reading Identity Crisis.

I’m assuming you probably heard or read a lot of these already but their worth repeating on the chance that you haven’t.

• The first four volumes of Superman/Batman are probably the best stand alone team up stories those two characters probably ever had. Between the four they deal with the kind of stories that only superhero books have done well. Things like multiple universe, massive crossovers, time travel, and introductions of legacy characters. They are also just damn good reads.
  
  
• Kingdom Come is another story that really could only be done well in a superhero book. If you haven’t read it then you really need too.
  
  
• Volume One and Volume Two of DC: The new Frontier are timeless superhero stories that really exhibits what makes them so special.
  
  
• All Star Superman shows what a modern version of a Silver Age story would like. This has the special sauce that made comics good back in the 60s and 70s and its one of the best Superman stories ever told.
  
  
• Superman: Red Son best example of an Elseword or Alternate universe story. Really good.
  
  
• Marvel’s Secret Wars should be required reading. Kind of like how Catcher in the Rye or To Kill a Mockingbird is in public schools. It’s a corner stone for comics.
  
  
• Crisis On Infinite Earths: If Secret Wars is Catcher in the Rye then Crisis is War and Peace. It is a tuff read for a new reader but it is masterpiece in terms of craft, storytelling, and the weaving of continuity.
  
  
• Identity Crisis was mentioned before but I’ll repeat it because it is the superhero story the deals with issues typically never addressed in superhero books. It is controversial for some of the things that happen but ultimately very good book.
  
  
• Superman: Our Worlds at War is probably a bit difficult to find at the point but it is a massive phone book size trade that show what a good multi author/artist collaborative crossover event can be like.
  
  
• The Long Halloween and Dark Victory are two timeless Batman stories. I don’t care for Batman comics but these books are so good that even I like them.
  
  
• Astro City just started back up again so a new printing of the first story should be just around the corner. It is a celebration of everything that make superhero comics great. Keep an eye out for this one.
  

Betrayal At House on the Hill. Kickass board game. Also, Batman Year One and Identity Crisis.

I would love THIS as the start to my Doctor Who comic collection. Barring that, I'd love to finally read Civil War.

I hope you enjoy it! Here are some of my favorites that I prefer over the Frank Miller stuff:

Jeph Loeb and Tim Sale (These are my favorites, lots of stuff taken from these in The Dark Knight film):

The Long Halloween

Dark Victory

Haunted Knight


Others:

The Killing Joke (You simply must read this one)

Batman and Son

Identity Crisis (Haven't read this one yet, but the plot sounds awesome!)

Non-Batman stuff:

Maximum Carnage (My first graphic novel that someone gave to me. It's spectacular!)

Watchmen