With the introduction of the 4004 microprocessor by Intel in 1971, a new era of computing power began, which flourished with devices like the 8085 and 8086. PCs became available in the market, their processing power enhanced every time a new processor was available to system designers. The reason behind the introduction of computers from the IBM PC, PC/XT, PC/AT to the latest laptops and think-pads may be attributed to the introduction of processors like the 8088, 80286, 80386, Pentium and Core2Duo. Computer Organization and Architecture: From 8085 to Core2Duo & Beyond (For JNTU) deals with external and internal features of these computers, taking into account the control unit (CU), processor details and their instruction sets, memory organization, external interfacing bus with standard input/output devices like the optical mouse or TFT screen, pipelining and parallel processing. Both modern as well as classical concepts are discussed with adequate weightage, and compared, as and when necessary.