In 1955 Topps released a throwback to their 1948-49 series of Magic Photos, which were similarly small cards that required the application of moisture and sunlight to "develop" the picture that revealed the answer to the very basic question on the card's reverse. They were issued in two sizes, a Large (relatively speaking) format edition of 96 subjects measuring 1' x 1 9/16'' and a Small edition featuring 126 subjects and measuring 7/8" 1 7/16". Movie Stars, World Leaders and several other groupings of subsets were created, with Baseball Stars among them. The first 96 cards in either size consist of identical subjects, with variance on the reverse to account for a subset numbering system that was rendered askew by the additional 30 subjects added in the Small set, inadvertent "high numbers" if you will.
The Large series of 96 was issued in panelized form in wax packs, while the Small series of 126 was issued as a true insert, with one small card wedged between the inner and outer wrapper of a piece of bubblegum-a method of distribution lacking in all manner of refinement. As a result, the Small cards are several orders of magnitude more difficult than the Large ones and they are, indeed, the rarest regular issue cards ever released to the public by Topps. The Baseball Stars series has 18 subjects in the Large size and 23 in the Small. These five additional Baseball Stars have been slow to reveal themselves over the years and the pop counts on these are minuscule. The other four "high number" Baseball Stars have PSA pops of either 2, or 3 and this card, of the immortal Lou Gehrig, is the sole entry in their database.
The only record of a Gehrig coming up previously was in an old 2002 "blind" lot offering from a large but now defunct auction house, and which was then sold anew that year. It's not clear if this is the card that surfaced two decades ago or or a different one, the latter scenario seeming more likely. It is PSA 4 in grade, as the corners have rounded and some obvious foxing is seen on the reverse of a well-developed card. This is perhaps the rarest card of the Iron Horse ever issued and it comes from Topps.