Isaiah, the first and earliest major prophetic book of the Bible. Isaiah wrote from 739 BC to 681 BC. The book contains some of the most beautiful poetry and memorable verses in the whole Bible.
"Unto us a child is born, unto us a Son is given. And the government will be on his shoulder: and his name shall be called Wonderful, Counsellor, The mighty God, the everlasting Father, the Prince of Peace." - Isaiah 9:6
"Therefore the Lord himself shall give you a sign; Behold a virgin shall conceive, and bear a son, and shall call his name Immanuel." Isaiah 7:14
"Then the eyes of the blind shall be opened, and the ears of the deaf shall be unstopped. Then shall the lame man leap as a deer and the tongue of the dumb sing: for in the wilderness shall waters break out, and streams in the desert."
Aside from beautiful poetry, there are many fulfilled prophecies: Israel to go into captivity; Israel to return from captivity, Jesus Christ to be born of a virgin, a new covenant to be made.
But the book requires patience and careful study, for Isaiah jumps context and speakers from one verse to the next. This is what frustrated me about it the first time I read it.
But read it even if you get confused; it's worth it.