Does anyone know when, exactly in the late 40's LGBs began showing 'A' 'B' etc editions with the letter on the back page? I have recently run across several copies of The Color Kittens that appear to be 1st editions, and with no difference in the binding, copyright, or titles listed on back, yet some have the letter A on the back page, and some don't. One website notes that there was a brief period when the edition was not noted on the .39 cent books. That tends to make me think the books with the A marked are earlier prints than the non-marked (as in 1949, the first year of publication for this title, the books still cost .25 cents, I believe). Seems to be confusing to a lot of people, as I doubt these are all first edition, first print, but they are listed as such (or "presumed"). The Color Kittens was published in 1949 and is #86. Thanks