It's time for a quote. This comes from The Silmarillion, after Fёanor, the greatest of the Noldor, betrays his brother Fingolfin and burns the ships that would have taken Fingolfin and his people to Middle-earth:
"Then Fingolfin seeing that Fёanor had left him to perish in Araman or return in shame to Valinor was filled with bitterness; but he desired now as never before to come by some way to Middle-earth, and meet Fёanor again. And he and his host wandered long in misery, but their valour and endurance grew with hardship; for they were a mighty people, the elder children undying of Eru Ilúvatar, but new-come from the Blessed Realm, and not yet weary with the weariness of Earth."
The Lord of the Rings is certainly an 'epic' series by some meaning of the word, but I feel that The Silmarillion surpasses it in both scope and poetry. In a small way, these two works could be compared to the Iliad and the Odyssey-- Iliad and The Silmarillion feature an epic engagement of nations, one featuring the Greeks and the other the Noldor. These works feature a large cast of mostly noble characters whose flaws lead to the ruin of many. Both epics end with a victory purchased at too high a price.
Odyssey and The Lord of the Rings tell more focused stories, following a few characters through their perilous journeys. This pair is probably more frequently read than the previous one simply because these stories are more coherent and flow better. However, Iliad and The Silmarillion provide context that make Odyssey and The Lord of the Rings more meaningful.