cheers
There are many stories writing in the comic world. Many are stories forgotten over time. Demon in a bottle is a classic. It is a story that will stay with Tony Stark's mythos as much of his origin of creating the suit. Although the art is and story feels dated when reading it today, it is still very important as an Iron Man fan.
Addiction is something many people suffer from. I am addicted to comics, I can't remember a day where I didn't get a fix of pictures and word bubbles. Demon in a bottle talks about a more important type of addiction, an addiction to Alcohol. Back in 1979 not may writers took a chance in writing mature stories. Comics where growing up and this story belongs besides greats like the Denny O'Neil and Neal Adams famed Green Lantern/Green Arrow run where to tacked drug addiction and racism.
Be warned that the art is dated, both style in the then young John Romita Jr. and in the fashion sense of the character. If you can't get over that the story will be hard to read. This is why the book is a 3.5/5. It is higher if you can get past the age of the book, but that score and hopefully not lower if you are use to the modern Marvel production level.
This is the only Iron Man hardcover I own and I am more of a DC reader, but I have not shame at all having this hardcover displayed in my bookcase with the likes of Grant Morrison's Batman, Alan Moore's Swamp Thing and the rest of the hardcovers. I suggest trying out the soft cover, it is cheaper and it a story all should read. Comics were growing up before Alan Moore's Swamp Thing. Alan Moore just took it to a different and higher level.
If you want to see that our ring leaders G-Man and Babs had to say about this book, here is the link to their trading views.
http://www.comicvine.com/trading-views-iron-man-demon-in-a-bottle/112-812/