I have three children, all 5 and under. Let me tell you, it gets a little crazy sometimes.
Two of my little
"Why do you have to roll around in the dirt?"
"Why do you need 12 toy cars?"
"Why did you pee in the yard?"
Someone recommended I read So You Want to Raise a Boy? and while ordering it off Amazon.com I realized it was very, very old. Only used copies were available. Mine even has a ripped jacket (see?) and a lovely inscription from a grandma to her son and wife, who I assume also have a rambunctious boy or two of their own.
I cracked open the book recently and have already read up to age 4. It contains some good insight into the different stages a boy goes through as he ages, but one thing really stuck out to me. This book really dates itself.
What I mean is, the book uses specific words and explanations that are so different from the modern norm. Comments sprinkled here and there that seem to shout, "This was written in the 1950s!" In its defense, some things can't be helped, like explaining that the father waits anxiously in the waiting room while the baby is delivered, for that was a social norm of the time. And words like "orgy" and "fondle" didn't used to have negative connotations like they do today. But I still find myself giggling. Then I gasped at the explanation of spanking, which of course is less-than-politically-correct these days.
What can we learn from this? If you want to make your book timeless, watch what you write. Consider leaving out popular modern words or phrases that are just a fad, and if you can, keep out references like fleeting technology gadgets and the like. Because readers should be focusing on the story or the information in the text, not the time period in which it was written.