There is no waiting for shipping on book three when you finish book two at 2:00 AM. The box set allows for what Riordan intended: a continuous, marathon read. You can track the overarching prophecy without breaking immersion. The emotional arc from Jason’s amnesia to the final line of Blood of Olympus flows seamlessly.
Buying the complete series together is the most cost-effective way for readers to transition from the original Percy Jackson stories into the broader "Riordanverse". heroes of olympus box set