How Do You Know Your Bail Bondsman is Trustworthy

You get a phone call in the middle of the night.  You’re relieved to find out that nobody is hurt but it’s your brother and he has been arrested and is sitting in jail.  His one phone call was to you and he wants you to help him get out of jail by calling a bail bondsman. How do you know who to call?  Do you pick one out of the phone book? Do phone books even exist anymore?