Ive picked up and discarded dozens of gardening books from anywhere from 2-50 years old. I find most of them to have out of date information.

However, the best rose resource Ive ever seen is Peater Beales Antique roses, he does cover "some" moderns, but its dedicated to the oldest classes, even the copy I have really needs updating, the grainy pictures wouldve been cutting edge when it was published, but compared to even modern day point and click digitals, the pictures are terrible. There is so much online resources about plants, planting, methodolgy , applications , that are current, that you can just research online in a few minutes.

You can also ask people who have grown what you are looking for right on gardenweb for decades, that resource is worth more to me then anything published in the 60's 70's 80's or 90's even.

IF you are talking about books that speak to the enjoyment of gardening, thats timeless, the same sort of satisfaction working the earth was had by humans for thousands of years, even if we couldnt relate to anything else, we can all understand the call of the earth, the fruit of the labor and the fulfilment of the flowers.

Silverkelt

For fiction, always my first favorite, The Secret Garden.

On gardening, anything by Christoper Lloyd. The WellTempered Garden is still my favorite of his.

There are others, that I love to read from the 1930's to 1950's, just for fun. Maybe "out of date"as far as some gardening practices but they were written by people with a true love of plants--Ruth Page, Richardson Wright, Gladys Tabor, Robin Lane Fox, tho he is a bit later
than the others.

Probably my newest favorite is "People With Dirty Hands" by Robin Chotzinoff. I hope it will get to be a classic!

I'm always fascinated by the English garden writers tho I have long since given up on creating a typical English garden; they do have a wonderful sense of style in their writing as well as in their gardening.

For information on plant taxonomy, my well worn Hortus Third. Michael Dirr for trees and shrubs. (I know he's an author, not a book title, but whenever a question comes up, it's "look it up in Dirr".) And there are a dozen more "favorites" I wouldn't do without!

Sandy

The Illustrated Home Garden Guide (1961) I bought this at a garage sale about 20 years ago and used it quite a lot. It's nearly 1800 pages long and references "everything" from soup to nuts. Of course now with the internet I rarely use it.

Anything by Des Kennedy. Smart, knowledgeable and very, very funny.