I have been studying the gun laws for awhile , I have some interesting bookmarks from my studies. One of the interesting threads is what it was like before the GCA 1968. People used to be able to do mail order of firearms. Also firearms were sold in gas stations and hardware stores. Seems that firearms were openly sold and obtained as easy as a hammer or saw.
I know you are looking for books, but there are some interesting threads out there as well. I'm sure others will chime in as well, but if you are interested I will focus on what it was like before the 1968 GCA.
The way the second amendment used to be with actual ads for mail order guns.
http://www.calguns.net/calgunforum/showthread.php?p=6514749
Origins of the Gun Control Act of 1968(Warning:LONG)
http://www.firearmstalk.com/forums/f97/origins-gun-control-act-1968-warning-long-26881/
Vintage gun ads recall the true America
http://www.freerepublic.com/focus/f-news/2427197/posts
Remember When You Could Buy These Firearms By Mail Order Before The Gun Control Act of 1968?
http://freerepublic.com/focus/f-bloggers/2692108/posts?q=1&;page=1
I didn't want to overload you with information, but I will add this. There were gun control laws before 1968 GCA, most notably the Sullivan Act 1911 in New York. There are references of some gun control activity in California with Los Angeles residents needing a conceal carry permit.
And Jim Crow laws in Southern States where one needed a permit from the sheriff to buy a pistol. But before 1968 GCA that part was rather moot as one could travel to other states and buy a pistol with no problems at the time.
Two years before the 1968 GCA. In 1966 The State of New Jersey passed the Sills Act . From this point on You need a firearms permit (FID) to buy a rifle, a blackpowder rifle and a BB gun rifle. You need to get fingerprinted, get a criminal and mental background check, character references and wait 30 to 90 days or longer for the background and processing and pay a fee and this permit is good for any amount of rifles. A separate purchase permit for each handgun (and this includes blackpowder and BB gun pistols).
And many suspect that even open carry was officially outlawed with passage of the Sills Act whereas before it was tolerated in some areas according to some posts I have read.
The law was written up in 1965, passed in 1966 by mainly Democrats, it was challenged and allowed to stand in 1968. Illinois FOID and Massachusetts ID card laws were inspired by New Jersey's 1966 Sills act.
I could write volumes on this, but hopefully it will help you in your studies. I need help too, I been looking for ANY information on ANY articles or write ups dealing with the original draft of the 1965 Sills act of NJ, the exact posted law in 1966 of the final passage of the Sills Act as well as who exactly voted for and against the 1966 Sills Act.
The only thing I have found on the net is the 1968 Burton vs Sills unsuccessful challenge but very little on the writing and passing of the act.
This piece of abomination was hoisted on the citizens of New Jersey two years before the 1968 GCA and have inspired two states to pass similar laws.