There was one semester during my first stint in college that I didn't have any classes I enjoyed and frequently ditched one or more of them to hang out in the library. I unearthed this and read it from cover to cover a couple times. A few years ago, I found it at the used bookstore I always go to and snapped it up.
Les Daniels, of course, wrote a few coffee table books about comics years after this. This came out in 1971 and is charmingly out of date in places, like when it's suggested Captain Marvel will likely never fly again and no mention of Stan Lee and Bob Kane taking credit for other people's ideas.
This book starts at the newspaper strips at the dawn of the newspaper boom through the present day of 1970. Lots of companies of the '40s and '50s are covered, not just Marvel and DC, as are underground comics. EC gets a chapter and the Wertham hysteria that led to the comics code and the death of EC gets another chapter.
Tons of stories are reprinted in their entirety in here. The origin of the Old Witch from Haunt of Fear, a Barks Duck story, a story from Creepy, and a Steranko tale from Tower of Shadows are the standouts but there are a couple dozen more.
While a lot of the info is out of date, like I said earlier, the stuff from the beginning to the 1950s plus the underground stuff make it a worthwhile read if you can get it for a decent price.