[veddox]

That's the standard introductory book we use at university. (Introductory meaning that most of it will see you through to your bachelor degree.) I find it a very good book with clear explanations and well-designed graphics. A nearly equivalent option would be Purves.

Downsides: if you're only looking for a cursory introduction to a few themes, it's probably going to be too thick (weighs in at ~9 pounds) and too expensive (> $100).

[caw]

Only if you buy the newest edition; an older edition should work fine for self-study since there's no classes to keep up with, and OP won't need the online component. I'm sure there's significantly cheaper copies of older editions where people just want to get that behemoth out of their bookcase.

[veddox]

True - and as the OP doesn't want to go into research, a few years out of date won't matter. (After all, it's not like there's been any major breakthrough in biology in the past ten years.)

[sn9]

I think the rule of thumb is that biology textbooks are 5 years out of date by the time they're published, so getting a slightly older edition is very practical.