E. Cobham Brewer 18101897. Dictionary of Phrase and Fable. 1898.
Hook or Crook (By).
Either rightfully or wrongfully; in one way or another. Formerly the poor of a manor were allowed to go into the forests with a hook and crook to get wood. What they could not reach they might pull down with their crook. The French equivalent is A droit ou à tort, or De bric et de broc. Either with the thiefs hook or the bishops crook. Mrs. S. C. Hall, in her Ireland (vol. ii. p. 149 n.), states, as the origin of this phrase, that when the ships of Strongbow were entering Waterford harbour he noticed a tower on one side and a church on the other. Inquiring their names, he was told it was the Tower of Hook and the Church of Crook. Then said he, We must take the town by Hook and by Crook. There is no such person as St. Crook mentioned by the Bollandists.
Dynmure Wood was ever open and common to the inhabitants of Bodmin to bear away upon their backs a burden of lop, crop, hook, crook, and bag wood.Bodmin Register (1525).
The which his sire had scrapt by hooke or crooke.