Hello Olga,
Most of the previous answers I think will be useful to you. However, another useful phrase is "avid reader". The word "avid" means "having or showing a keen interest in or enthusiasm for something." We often use the phase "avid reader" to describe someone who very much loves reading and does it a lot. For example,
"Mary is an avid reader and usually reads several books a month."
"Steven is an avid reader, and is very knowledgeable on most topics that interest him."