It prompted me to look through it for the first time (I owned the 1e MM & FF, but that's it...until recently some S&W monster books.).
The fella in the comments is 100% right. The illustrations and format of this book is very, very, very, VERY bad. Yikes!
As a parting shot --- the one-monster-per-page format sucks. Big time.
That was the Monstrous Manual, wasn't it? 2nd edition didn't start with monster manuals. Instead they had "Monstrous Compendiums". Monsters would go one per page, three hole punch, and as you bought more compendiums to add to your binder you could put everything in alphabetical order.
Yeah, it didn't work out so well in practice. I was happy when the Monstrous Manual came out, it was a worthy replacement.
As for the one monster per page format, at the time it seemed to be a revelation. You'd be less likely to be completely baffled by a monster, like you would be with the Tirapheg from the Fiend Folio. Now it's more like meh. Some monsters can use the extra information (ie Githyanki/zerai in Fiend Folio). Others don't need it. And the Ecology section was always useless.
3rd edition seemed to have introduced my pet peeve. "This is an ambush predator". *puke* Followed close behind by "these monsters act as shock troops" (but that at least came from Gary with the Bearded Devil).