what is deffrence between this sentence (kitap okumak çok guzel ) and this ( kitap okuma çok guzel ) 

kitap okumak (to read a book)

oku+ma(verbal noun)--------->okuma (reading a book)

Kitap okumak çok güzel. (It´s very nice to read a book.)

Kitap okuma çok güzel. (Reading book is very nice.)

We use this pattern by the infinitive mood almost everytime. That´s to say: (almost always) : kitap okumak çok güzel (it´s very nice to read a book)