Getting my 15 month old to sleep without rocking?

Honestly I think the best way is to just put him in his crib and let him cry it out until he gets accustomed to putting himself to sleep. At least that is what my pediatrician tells me. Now if I could just take the advice myself. I personally thought it sounded cruel but I may just have to try this so that I am able to get some rest myself. Good Luck