Is it illegal to rewrite a copyrighted book?

Go ahead. Write it. It's good practice. Just don't show it to anybody.

the reason the book is copyrighted is so that nobody tries to rewrite it, if you rewrite it and don't sell it your fine, you gotta give parenthetical citations or something, like give full credit of where the ideas came from (author) and just don't sell it, cuz they will go after you if they find out

No, it's not illegal. In fact, you can legally rewrite it word for word -- as long as it's solely for your own use. Otherwise, best write your own book.

yes, unless it's public domain. i mean, technically you would be able to if you rephrased it, but i wouldn't do it. the owner of the copyright would probably come after you. you don't want to deal with that.

Plagiarism.

Quotation = legal

Removing copyrights, or deprecating it on ur book = Not even illegal

it's illegal if you make money off of it unless you get permission (in writing) from the author.

It's illegal if you try to sell it. Otherwise, I believe it's okay. I personally wouldn't, but it's up to you.

No, becuase it would not be the same book. You would just have to contact the author and on the cover, write Retold by: YOUR NAME :)

It's illegal, immoral, and unethical.