The x86 Intel Microprocessors are the most widely used processors in the world today and have many books that describe them In Depth.
Microprocessors are used in PCs. Microcontrollers have pre-determined tasks that are used in tiny devices like MP3 Players, Microovens, Digital Cameras, etc. that provide the desired tasks.
There are Chipset-based Motherboard that evolve along with microprocessors.
The Intel Family Of Microprocessors: Hardware and Software Principles and Applications with CD
Microprocessors: The 8086/8088, 80186/ 80286, 80386/80486 and the Pentium Family