What Age Level is Doc Wilde meant for?

The book is meant for anyone 10 and up.

My son, a very advanced reader, thrilled to its cliffhangers and monsters when he was 8. Many adults have read it and loved its retro action and in-jokes and allusions.

There has been some confusion about this because on various bookseller sites, the "Suggested Reading Level" is showing up as 4-8.

It's not. Somewhere along the line, some bad info got into the system, and I'm trying to get it fixed.