Part of a 22-card set that was, according to conventional wisdom, never intended to be released by Topps, the 1968 Test basketball issue is quite rare and highly desirable today.  In 1968, Topps had no license to produce NBA cards, though the existence of this issue serves as evidence that they were at least considering it.  In the early 1990s, cards from the issue began to surface in the hobby, and just over 200 cards have been graded by PSA. 

Earl "The Pearl" Monroe broke into the NBA in 1967 and was, of course, part of the landmark 1969 Topps basketball set, which many collectors consider his rookie card.  This example obviously predates that, and is an extremely rare and desirable card as a result.  With just 12 examples graded by PSA, this is a tremendous card, well-centered and clean, with light corner wear reducing the grade.