child or a book or a painting or a house or a wall built or a pair of shoes made. Or a garden planted. Something your hand touched some way so your soul has somewhere to go when you die, and when people look at that tree or that flower you planted, you're there. It doesn't matter what you do, he said, so long as you change something from the way it was before you touched it into something that's like you after you take your hands away" (Bradbury, 73).

Essentially, Granger is telling Montag that he needs to leave his mark on humanity before he dies by giving back and positively impacting society. Granger is encouraging Montag to leave a legacy, which Montag will have a chance to do by helping rebuild a literate society.

In Granger's last speech to Montag in this dystopian classic, after witnessing the bombing of the city Montag has just successfully fled from, Granger tells Montag to basically remember that their job is to remember all the mistakes that have been made in the past so that hopefully humanity can enjoy a better future:

And when they ask us what we're doing, you can say, We're remembeing. That's where we'll win out in the long run. And someday we'll remember so much that we'll build the biggest goddamn steamshovel in history and dig the biggest grave of all time and shove war in and cover it up.

Granger's emphasis is on using all of the knowledge that they have learnt from book to make sure that the future is better. He says that humans, even when they had access to books, still made all of the same mistakes. Hopefully this time things will be different and the book people can be key to securing a brighter future for the human race that does not involve forgetting the amassed wisdom of the ages.

In the novel Fahrenheit 451, Montag runs into Granger and his small band of secret bookkeepers outside the city. Montag is fleeing from the mechanical hound after his house is ransacked, and they are looking for the books he stole and hid.

Granger first helps him to evade the capture of the Mechanical Hound by giving him a drink that changes the chemical makeup of his sweat, which the hound smells to follow him. This throws them off his scent and forces them to capture someone else in his stead.

After that, Granger tells him the story of the phoenix and how it rises from the ashes after death. Granger explains to Montag that humanity is like the phoenix: they will rise again. However, humanity has the capacity to remember its mistakes and become better, to prevent their death the next time around. This is the main lesson Montag has learned⁠—that if they record their history and rebuild, they can make society better. They all return to the destroyed city to rebuild it, having memorized various books so they can rewrite them.

Granger teaches Montag how to evade the pursuit of the mechanical hound and others, and how to memorize books.

Granger is “the man who seemed to be the leader of the small group.”  He gives Montag a drink that will “change the chemical index of your perspiration” so that he will smell like two other people and the mechanical hound won’t find him.

Granger explains that Montag lost his followers at the river, but they have to catch someone so they will find a scapegoat.

The show's got to have a snap ending, quick! If they started searching the whole damn river it might take all night. So they're sniffing for a scape-goat to end things with a bang. Watch. They'll catch Montag in the next five minutes! " (part 3)

The mechanical hound takes the man, and his face is never known in focus so even his friends and family would never know.

Granger introduces him to the various men in the secret book society.  They have perfected their memory so that they can remember anything they read once.  Each one is a different book.  They teach Montag, and he has a sense of purpose.

Upon first appearances, Granger and his friends seem to be a bunch of vagabond homeless people, hanging out on the fringes of society, down on their luck.  As Montag talks with Granger, one of those men, however, he realizes that many of these men have chosen to live this way, or have been driven to this life because of the restrictive, stifling, and sometimes even threatening structure of their society.  Granger is not an illiterate and down-on-his-luck homeless person; rather, he is well read, intelligent, wise, and content with is lot in life on the fringes.  He has even written a book called "The Fingers in the Glove; the Proper Relationship between the Individual and the Society."  There are professors and authors galore in the group of outcasts.

Montag, no literary man or professor, feels intimidated by their smarts, and states so; he is just a simple fireman.  Granger confesses that back in the day, he "struck a fireman when he came to burn my library," and that ever since that day, he's been on the run.  That is quite a discovery, because Montag himself is a fireman.  Granger is not afraid or intimidated though--he asks if Montag wants to join.  There are no hard feelings.  The men unite together, with their memorized books and wisdom, and will be the force that hopefully rebuilds their society better than it was before.  I hope that helped a bit; good luck!