In the end, I picked those that showed both the person and the task being pondered or the object involved in that task. First Honorable Mentions:
Carol 202 (carol202) for Setting up the Tent:

Thomas Dunn (tddunn) for One of many paths 9500:

Juan León (jlben) for the untitled:

Maaike Huizer (emmelafoto) for Laptop:

Now the Winners:
Third place Jeroen Bosman (hiero) for Reading Between the Lines. Superb technically, it is clear we are dealing with a consumate and experienced photographer:

Second place Enrico Martinuzzi (ee66) for Cake Attack. What a delightful image of a child trying to solve the insolvable puzzle of having your cake and eating it, too. What an outstanding expression on the child's face, and the gestures to match:

And the First Place goes to Kirsten (kirstenmary) for the untitled image:

A fantastic combination of intense concentration, composition, and post-processing for the subject.
Congratulations to all. There were so many excellent entries (and some baffling ones, too
