I couldn't tell you what book ( I used an online study program), but I can tell you that my test contained alot of SCSI questions regarding cables, termination, setting ID's (physical jumper settings), and troubleshooting. Other than that, there were a couple of IDE questions, IRQ questions, and DMA's. All of the later were very easy, common sense questions. I found that it is best to go through the test and answer only the questions you know for sure. If you don't know or are debating an answer, mark it and come back. I know it doesn't matter how many you get wrong(cause of the secret scoring system), but I had 16 marked questions at the end, and I guessed on a few and still passed with a 667. Good Luck on yor retake!