I say it depends on what you are looking for.
I've seen a lot of newer books that lack on quality fish care and background. I think it is important to know about different parasites, what they look like, what different diseases/issues look like for different fish. I also think it is good to have a bit of fish physiology along with pathology.
Most older books I've read through have a decent background. That is why I buy books. To get a diverse background of information that i CAN'T (easily) just get from the internet.
Newer books tend to have less background info and more pictures. The pictures have less information. It tends to be the quality I would find if I went LIGHTLY through a forum, and collected the tank/pic of the month for a select few critters.
One thing that I find interesting is that the new books have not updated the reef equipment sections as I'd like to see. They stick to the barebone concept and barely chat about the potential design and engineering aspect of designing an ecosystem.
Lol, I also just hate books that lack a professional tone. Most of the newer books I've seen are too conversational. I don't want to feel like I may know more (or be able to articulate at a higher level) than the people writing the book.
So, I have also have that bias when reading aquarium books.
-so end point, for my tastes, I would question whether the newer books are worth buying.
