The reaction involves two molecules of cyclohexanone reacting in the presence of a base (dilute NaOH) followed by heating (acidic dehydration is also common).

1. Aldol Formation: One molecule of cyclohexanone forms an enolate ion (removal of $\alpha$-hydrogen) which attacks the carbonyl carbon of the second cyclohexanone molecule. This yields a $\beta$-hydroxy ketone (ketol) intermediate: 2-(1-hydroxycyclohexyl)cyclohexanone.
2. Condensation (Dehydration): Upon heating, a water molecule is eliminated from the $\beta$-hydroxy ketone (specifically involving the $\alpha$-hydrogen and the $\beta$-hydroxyl group) to form a stable, conjugated $\alpha,\beta$-unsaturated ketone.

The final product is 2-cyclohexylidenecyclohexanone.