I drew this card in a reading yesterday, and I had a sudden epiphany about what I believe it means...
I don't think the books are things that this King has read -- I think they're things he's written
. I had this flash that they're essentially journals. They're all of his experiences, reduced down to writing, and the books make up his body, because our experiences in very large part make up who we all are. There are still more books in front of him because he's still living and experiencing, and he has more journals to fill. In the meantime, he's now filled up so many journals which have since become incorporated into who he is, that he's now tall enough, and has a good enough vantage point to see and navigate, and adequate leverage to steer, that he can now chart and realize whatever course he likes through the sea of emotion that he's sailing. Before he was this experienced and mature, he would have been forced to sail blindly more often, and his steering would have been less effective. Now he's ripened into the King, though, and he's smart and strong and skilled.
Also, he's tall enough now that the stars on his crown are at exactly the right height in the image to place them on the same level as the actual sun and moon in the sky -- I think this part of the message is that the King can serve as the bridge between the ocean of feeling below, and the celestial realms above.
And finally, one of the books has some writing on the edges of its pages, and seems to say "La Stra," whatever that might mean (something in Italian?). Whatever it might literally signify, though, I couldn't help but notice that a very minor rearrangement of letters yields the word "astral." I know I might be reaching here, but I'm wondering if the card is also saying that with just a bit more mastery of the emotions, the King will also conquer the astral plane, and things related to it, such as lucid dreaming...?