The specifics of the design philosophy changed over time. Monster Manual 3 is the best source for opponents who fit the newer philosophy. This is because earlier monsters had too many hit points and too little damage -- they were less of a threat and more of an annoyance or slog.

No book I own actually spells out the design philosophy (either the original version or the MM3+). So far as I know, what we talk about is just reverse-engineered from the numerous available examples. But DMG1 does describe a lot about how monsters fit into encounters, in terms of quantity, role, challenge, reward, that sort of thing. It might give some insight beyond the bounds of 4e.

I like to suggest people read DMG1 regardless. The sections on player motivation and campaign design are worth the price of admission by themselves.