[pwg]

You left out the two most significant data points to help us help you. What is the scan resolution and bit depth of the images inside these pdf's. Because if you have scanned these books at 600dpi 32-bit color, then no wonder page flipping is slow. If so, you should reduce the color depth to 1-bit (black & white, assuming when you say "book" you really mean "book" as in black text on white paper). Going to black and white would likely seriously reduce your file sizes, while also seriously accelerating your page flip rate.