Record | book:Walt Disney's It's a Small World, with the song

RCA introduced the 45 rpm single record in 1949 as a smaller, more durable, and higher fidelity replacement for earlier 78 rpm disks. Music singles on 45s served for decades as a low-cost entry point for young fans and turned single record sales into a prominent gauge of the popularity of songs and musicians. The durability of the single record, which was later pressed at the standard LP rpm of 33-1/3, made it suited for use as a product for children, notably in sets with a matching illustrated book.