I think the word by is ambiguous: it could mean that you have listed (quoted) the names by means of informers (still a normal sense of by today). Alternatively it could mean that you have gathered the names in order to provide useful information. From the OED: 36.a. The sense of ‘means’ sometimes approaches or passes into that of ‘cause’ or ‘reason’: Because of, on account of, in consequence of, through; in virtue of, on the ground of. †by so, by that: therefore.
Thank you for the explanation. Could you please rephrase the line so that I can understand it better? I can try but it'll probably be wrong
... (a book) in which you have written the names you have received from your informers... OR
... (a book) in which you have written the names of offenders, (and this book) provides useful information...
Ugh, that makes litte sense to me
I think "by your inteligence" is less likely to mean "because you are intelligent" than it is to mean "through your sources" (ie informers, wiretapping, etc. - we speak of 'intelligence agencies' for 'spy networks': ['humint', for 'human intelligence'] or 'information gathering' by other means, such as electronic eavesdropping, spy planes/drones, etc.; sorry, I forget the abbreviation for this one.