Why socialism book written by?

It's impossible to say "the socialism book" as there are many books written about socialism! It's a broad and complex topic with many different perspectives.

To give you a helpful answer, I need more information. Please tell me:

* What kind of socialism are you interested in? There are many different kinds of socialism, like Marxist socialism, democratic socialism, libertarian socialism, etc.

* What are you looking for in a book? Are you looking for a historical overview, a philosophical argument, a practical guide, or something else entirely?

Once I have a better understanding of what you're looking for, I can recommend some specific books on socialism.