A rubaiyat is a quatrain or four line poem. Omar Khayyam was a poet, astronomer, algebraist and former tentmaker. Each rubaiyat reads like a haiku and though short often time requires contemplation. Put together they form a 444 line examination of the human condition in terms of love, life and death, nature and science.
The most famous translation of the Rubaiyat was done by Edward Fitzgerald in 1852. He apparently took quite a few liberties with the translation, turning vague poetry into gay poetry. Although the version I read still shows Fitzgerald as the translator, the text is very different (and I suspect cleaned up) from Project Gutenberg has online. The copy I read was a "book club" edition and I suspect the publisher didn't want to insult the sensibilities of its readers (pity).
Although the text I read was cleaned up, I did enjoy the spirit of the poems. Someday though I would like to own an older edition, one that hasn't been cleansed.