Which one of the gods is angry with Odysseus, and why?And in which book can I find the answer for myself?
Poseidon has been angry with Odysseus for quite some time and some of it stems from the fact that Odysseus devised the plan by which the Greeks defeated the Trojans, and the Trojans had a particular fondness for Poseidon who returned the feeling.
So Poseidon is intent on preventing Odysseus from returning home and helps to set up a number of obstacles that make his return more difficult. The sea is against Odysseus and many storms blow him off course including the massive one that leads him to the lotus eaters and then to the land of the cyclops (book 9).
This of course led to another incident that directly provoked Poseidon since Odysseus ended up blinding Polyphemus, one of Poseidon's sons. When Polyphemus curses Odysseus in the name of Poseidon during his rage at Odysseus and his men as they escape the island.
Just to finish that last sentence, which I noticed wasn't quite complete, when Polyphemus curses Odysseus this further enrages Poseidon who redoubles his efforts to be sure that Odysseus never makes it home.