what is FPGA & ASIC?

i know the functionality of PAL,PLA. but i could't understand the logic blocks of cpld & fpga. Give some details & web address for the same. which book i have to follow? i have some doubts. 1.Is FPGA only for digital ckts? For analog circuit design what we r using? 2.What r the other technologies(like FPGA & ASIC)existing for IC Design(digital & Analog)? 3.What is EDA tools? 4.i need some details that hardware design Engineer must know.