This old paper tells the history of early Intel CPUs and discusses their features and major design decisions: the 8008, 8080, 8085, and 8086. The paper provides interesting technical and historical tidbits, such as the reason why the 8008 was little endian and hence later CPUs.
Dasm8080 is a great Intel 8080 disassembler with nice features such as the visualization of bit patterns and the detection of opcode and data sections.