Sooo... Is the small book not accusative?? It must be, right?
I read the book.
The book is accusative because of the verb.
I am the man.
As if the man isn't accusative now.
If I'm correct, I've seen this in multiple questions already, so I hope we can make a change.
For people that don't fully understand: Accusative case is when it gets an n, here it turns into malgrandan libron.
An example in English:
It is him.
It wouldn't be it is he, since he is now in the 4th case, so it turns into him.
Although most people understand this, just for the younger people learning Esperanto. (even though I'm 14 myself ;))
From what I understand it, estas is treated as "Equals" in terms of accusing. "it equals he" and "he equals it" means the same thing, so they skip the accusative ending, unless you want to show direction: "It equals there" -> "Ĝi estas tien"
Estas means is, and is is a linking verb in English. When you have a linking verb a good way to check it is saying to yourself does the noun equal another noun or adjective in the sentence. Example: She is a girl. She is the subject/noun. A is always an adjective since it is an article. Is is a linking verb. Now we ask ourselves, what does she equal? We now know that she equals a girl. That makes girl the linking verb compliment, and since it is a noun it is a linking verb compliment noun, instead of a linking verb compliment adjective. If you don't understand. I can explain more, just write on my page. Hope this helps!