correct my sentences

[user_gary]

I am book. I have been used for many purposes. I could be missing after a 10 decades because of internet facility.

Is there any word to replace in place of `missing' and `10 decades'?

Also, correct my sentences.

[queenbu]

I am book. I have been used for many purposes. I could be missing after a 10 decades because of internet facility.

Is there any word to replace in place of `missing' and `10 decades'?

Also, correct my sentences.

I am a book.

10 decades - a century, hundred years

'missing' in what sense? Meaning 'useless'?

[user_gary]

I am a book.

10 decades - a century, hundred years

'missing' in what sense? Meaning 'useless'?

Thank you.

missing I mean (unavailable)

[queenbu]

obsolete?