The time is perfect for a short, smart purse book. The "good bag" has nudged out shoes, jeans, and jewelry as the must-have fashion possession. Despite price hikes -- $1,445 for a Prada bowler bag that once cost $940 -- the craze for high-end purses helps fuel the booming luxury-goods market and, via knock-offs, hugely influences the $6 billion-a-year mainstream handbag industry. But purse mania isn't just an outgrowth of a strong luxury-goods...