To the left of each book title is an icon based on what you have set for that book. Here is an explanation of what each icon means:
You have not set any status on this book.
You have marked that you have read this book.
You have marked this book as “Want To Read”. You can see a list of all books marked as this in your library.
You have marked this book as “Did Not Finish”.
You have marked this book as “Not Interested”, as in you have no interest in reading it.
Only you can see what you have set each book status as. You can change it at anytime by clicking on the icon, and choosing a different status.