So, I picked up a few Nancy Drew Diaries from a library, and noticed something odd about "The Sign in the Smoke", it's 272 pages long! According to Amazon, the other Nancy Drew Diaries books are 195 pages long....except for "Sabotage at Willow Woods", which is only 176 pages, and "Secret at Mystic Lake", which is 160 pages.

So I decided to look at the Hardy Boys Adventures, and look at this:

The Battle of Bayport: 160 pages

Showdown at Widow Creek:128 pages

Bound for Danger: 144 pages

Most of the books are either 128 pages long, or 144 pages long, a 16 page difference. From what I've heard, the text size is smaller in the Hardy Boys Adventures series then the Nancy Drew Diaries, but this doesn't explain the varying book lengths. Compare this to the Digests, UBs, and Casefiles. All three series have pretty consistent book lengths, some books are slightly longer or shorter then others, but not this much of a difference.