[Grammar] Is the superlative always preceded by "the"?

[Rosamond00]

This sentence was mentioned in a grammar book as the correct grammatical form for another common mistake, but it sounded awkward to me because "the" was not used before the superlative:

"I've tried all of the machines and this is easiest to handle"

The common mistake is
"I've tried all of the machines and this is easier to handle"

 

[José Manuel Rosón Bravo]

Hi Rosamond00,

“I've tried all of the machines and this is the easiest to handle"

The easiest machine among other machines.

The common mistake?

"I've tried all of the machines and this is easier to handle"

I think this second sentence is right.

Regards,

José Manuel Rosón Bravo