I think my interest started because I was a comic book collector and dealer from 1966 to 1976, but when I first saw a pressbook, I was super-impressed, and was amazed that they almost always cost less than anything else on a movie, and less than a single good scene card. When I saw some older pressbooks, especially the MGMs, where the covers are exactly the same as the window cards, in full color, I was hooked.
This was in the mid-1980s. I started buying every large group of pressbooks that were out there, and I bought many thousands, and lots of them were just a couple of dollars each, and sometimes less, and the better older ones were mostly $25 to $100. When eBay came along, a lot of former theater owners and their families started putting lots of pressbooks online, and I bought thousands more.
Around five years ago I made a big effort to start organizing them. I had at least 25,000. I first sorted out all the ones from the 1960s and 1970s (they pretty much quit making them at the end of the 1970s, when presskits took over). I compared what I had from 1960 on to my database and found I had all but the most obscure titles.
I did some sorting on the 1950s and earlier, but then got sidetracked when my auctions really took off. A wild estimate would be that I have maybe 50% of all the titles from the 1950s, and maybe 25% each from the 1940s and 1930s, and maybe 10% from before 1930.
I used to check eBay every day for pressbooks, but I started finding so little that I quit a couple of years ago.
I have some great ones (like King Kong, Bride and Son of Frankenstein, GWTW, Casablanca, Wizard of Oz) but am missing a lot of the very best ones, because they are SO expensive and/or rare.
I still occasionally buy some large groups of them, and I long for the day I can get them fully organized. Imagine a website where every page of every one I have was available for reference?
Bruce