Isaac Albeniz is one of the most famous of the Spanish romantic era composers. In his life he was renown both for his compositions for piano and his own virtuosity on the instrument. His music is also very Spanish, and although played often enough, it's certainly not as common as compositions by the True Titans of Piano like Liszt and Chopin. Instead today, you're more likely to hear Isaac's songs at a classical guitar concert where transcriptions from his Suite Espanola have become performing staples.
It's unusual for a man who is largely unknown to the general public to have a mythology built up over the years, and not surprisingly, much of the mythology about Isaac came from Isaac himself. Now it is true Isaac was a child prodigy, but not that he stowed away on a ship to the Americas and ended up playing piano in waterfront dives in New York City. In fact, his first trip across the Atlantic was very nondescript. In 1876, he went with his parents to Havana where his father had been appointed customs inspector. Isaac soon returned to Europe where he entered the Brussels Conservatory and soon gave a well publicized (and well received) concert tour. The story he studied with Franz Liszt is, alas, also not true although he did once travel to Budapest to meet Franz. But when he got there he found the great composer and pianist (and father-in-law of Richard Wagner) wasn't home.
Isaac's virtuosity can't be doubted - his concerts received rave reviews wherever he appeared. But due to his relatively short life (Isaac died in 1909, eleven days short of his 49th birthday), there are not many recordings where he himself sat at the keyboard. What records made were during the pre-electronic days and have suffered the ravages of time where the snap, crackles, and pop of the cylinders obscures Isaac's actual playing. So it is virtually impossible to compare Isaac's to today's piano virtuosi.
Isaac himself had no objection that guitarists more or less quickly commandeered his music, and at one time he supposedly told his guitarist Francisco Tarrega his music actually sounded better on guitar. The most popular transcriptions are from Isaac's Suite Espanola, particularly Sevilla and Granada. There is also Asturias, one of the common showpieces for the classical guitar, which has the double virtue of sounding impressive but not being really that difficult.
Books on Isaac are few and far between. The most definitive biography is Isaac Albeniz : Portrait of a Romantic by Walter Clark (Oxford University Press, 2002). Although this book does debunk many of the Albeniz myths (which weren't known by most people in the first place), it is a rather hard volume to find at a reasonable price. On the other hand, a very brief but nice biography of Isaac and a discussion of his music is at http://www.lib.umd.edu/PAL/YALE/albeniz2.html, which also mentions the Real vs. Mythical Issac. If you look and are careful, the Internet can be a good place to find accurate information.