From the introduction:
The Tomb of Yearon is an adventure for designed for four 8th to 10th level player characters. It is advisable that the party retains the services of a rogue, a less diverse party of characters may have trouble surpassing some of the puzzles within.
The Tomb of Yearon was created as a starting point for a campaign in which the player characters recover the first part of a three part magic item. It could just as easily guard any number of special magic items.
Players should be able to complete the Tomb in an evening. The module is short enough to use as a sidetrack adventure or as part of a larger storyline.