Complex sentence: The first edition is readily distinguished from later editions by its lack of a silhouette on the front cover, and blank end pages, however a few printings occurred (through 1932) before these trademarks were added to the series.
Split into simpler sentences: The first edition is readily distinguished from later editions by its lack of a silhouette on the front cover, and blank end pages. However, a few printings occurred (through 1932) before these trademarks were added to the series.