A great book and a warning to all of us to let God have his way with our lives and have pity for the lost and unsaved. The key to why Jonah ran away from God's command is actually in Ch 4 Verse 2
2 And he prayed unto the Lord, and said, I pray thee, O Lord, was not this my saying, when I was yet in my country? Therefore I fled before unto Tarshish: for I knew that thou art a gracious God, and merciful, slow to anger, and of great kindness, and repentest thee of the evil.
In other words, "didn't i say this is what would happen before I left my home? that's why I fled because I knew you are gracious, merciful and slow to anger, etc". He was a Hebrew and looked down on the pagan Ninevites, so he didn't want to have to preach to them. He didn't want to see them repent and see God have mercy on them. Really kind of shocking when you think of it and you have to wonder why God bothered to choose Jonah for this particular job.
Then later in the chapter you see him wishing he were dead and enjoying the shade of the gourd God provided. But when the plant dies God chides Jonah for having more pity on the plant than the entire city of Ninevah.
Jonah was a grumpy, unhappy man even though God used him for a great job.