Not at all.
The first one is very big, it doesn't have too many pages, but there's a lot of very serious information on them - architectonical, liturgical, historical. There are many pictures tehre too, because the subject demands it.
The second one is also big, not too many pages, but lots of content. It contains historical and religious texts, very detailed.
The third one has pictures and texts, it has the length of an average book, over 200 pages. Easy to read, very interesting.
The fourth is a play, it has 3 acts, and it's an over 100 year old publication. It's has the size of a pocket-book, because it's a part of a cheap library set, so it's under 200 pages, but it only contains text. And it's written in a dialect, so it's not an easy read.
The fifth is almost 400 pages long.
The last one is a pocket book, it has drawings of the planes along with detailed information. Small, but compact.
As you can see, these are all serious books.