okay, one more chenford post: I headcanon that when Lucy recorded the audiobook, she read it the same way she did in the shop, with her own little notes and comments. that "read by the best rookie you've ever trained" was just the beginning.
she adds more comments along the lines of "that is so true!" and "such a great advice, don't you agree?".
there are several comments on the sexism of the book, and anytime it refers to the police officers as "men", she makes some kind of remark about it: leaves a ridiculously long pause before saying "men" in a flat voice, or sarcastically noting that of course women can't be police officers, or just straight up changing it to gender neutral language.
every once in a while she just announces "repeat that last part back", and she leaves enough space for him to roll his eyes, complain that he won't do that, wait for her to continue, and eventually repeat it anyway. it's all timed perfectly, and by the time he's halfway through, he doesn't complain or roll his eyes, and the silence is still perfectly timed.
a few times she ends up rambling about a related study she heard about at college and then goes back to reading as of nothing happened.
Lucy 100% recorded some kind of personal message after the end of the book. she finished the book, and there's a long silence, so long that it seems like there is nothing else there, and then a few quiet words of encouragement. (and this fic about it by Savethecat_heroics on ao3 is also 100% canon in my mind.)