Quoting myself posting under another alias in BT:
The original series started under Kadokawa Sneaker Bunko in 2001, a light novel label. They do not originally have English titles other than romanized titles, and every book is done by a different illustrator. It then moved to Kadokawa Bunko, a normal novel label, in 2006, and got the "You Can't Escape" as the English title for volume 1, with a new illustration. The latest print got its English title changed to "The Niece of Time". Hyouka has undergone close to 30 prints AFAIK for the past decade. It seems like with the anime, Kadokawa wants to remarket the series back to the LN market with a new anime-ish cover without replublishing it back under its LN label, which has sparked some negativity among the readers.
This is the old-skool version of Hyouka (ie. volume 1), which you can't find on Amazon anymore:
This is the version when it moved to Kadokawa Bunko. You can find this version in most bookstores:
This is how the anime-ish cover look like:
On a side note, quite honestly, there are times when I feel like sleeping while reading volume 1, but the anime did an outstanding job with its 'extra effects'.