I read in book Unix concepts & application by Sumitabha das, & also many articles which i get from Google search, every where i got very ...(Low deep or information which proper for greenhorns not for ranch hands i think so! ) information with diagram.
The kernel is the core of the operating system. It contains all the basic, low-level things that are needed to make the computer work, and provides a framework for all other software to run on.
There are different ways to organize the kernel. People have come up with different designs for the kernel of their operating system, and that's what all those different kinds of kernels mean. You'd have to read all those Wikipedia pages to understand exactly what the differences between them are.
The Unix shell is one of the basic pieces of software that comes with every Unix-like operating system. It's like the command line prompt in Windows (but more powerful). The Wikipedia page describes it quite nicely.