Where other books in this series have tended to concentrate on mundane and magical variations of a standard adventuring item, this one is longer an analysis of the basic idea. What are iron rations? How long will they last before going off? What exactly are the effects of missing a meal? And to what extent to common spells such as Create Water and Goodberry make a difference?
Of course, in addition, there are variations for each of the player races, plus a subterranean version for the likes of drow. (I'm not clear why this latter would include moss, which requires sunlight to grow, but that's more a matter of the nature of the Underdark than anything else). There are a couple of magic items, but these are both fairly straightforward.
As seems to be common with this series, there are a number of spelling errors, and quite a lot of whitespace that means the 12 pages contain rather less information than you might suppose. But, otherwise, production values are fairly good.
Primarily, this is a booklet to add detail to your games - ensuring that your characters don't starve to death, while having food be realistically perishable. And, if you want that extra detail, I'd say this is pretty useful, and a good entry in the Adventurer Essentials series.