A new function of my book?

Today I asked a colleague if he had read my book. When “push came to shove”, he said he has it next to his bed and will read it when he haSleepingZs problem falling asleep. I explained to him that he might be disappointed (not the content of my book). It is because another colleague “confessed” that he did exactly that and read four chapters before concluding that it was not a function of my book.

Well, my book can be used in many different ways but I am afraid putting people to sleep is not one of them (as far as I know).