As with most collectibles during these inflationary times, collectible children's books currently have higher demand than pre-Covid, resulting in higher prices, and less collectible books on the market.
With estate sales in mind, in particular to children's picturebooks (i.e. exclude 'chapter books') in dust jackets, some basic tips.
1. Knowing Next To Nothing: Picturebooks from mid-1960's to mid-1980's
These will have a number line and pre-date bar codes. The number line will make it fairly straight-forward to identify whether the book is a first or early edition, and bar codes began in 1985/1986 therefore the book is over 35 years old.
2. Having General Bookselling Experience: Picturebooks before mid-1960's
It is more difficult to identify early and first editions picturebooks published prior to the use of number lines. As an experienced bookseller you can 'smell' a decent purchase via the DJ price, which will approximate:
- 1930's $1.00 or less
- 1940's $1.00 to $2.00
- 1950's $2.00 to $3.00
- 1960's $2.50 to $3.50
If the DJ is clipped, then look for the copy on the DJ flaps - the other books mentioned will provide a good idea of the year of publication of the book in hand.
3. Knowing A Little Goes a Long Way: Caldecott Medal and Honor Books
While it is unlikely to find a first edition Caldecott Medal book - of any year - in estate sales, these have very solid market value. See the American Library Association's website https://www.ala.org/ala/alsc/awardsscholarships/literaryawds/caldecottmedal/caldecotthonors/caldecot...
Caldecott Honor books have nearly as much collectibility and demand. And it doesn't have to be a first edition as early printings of both Honor and Medal books with DJ's are very sellable on eBay, especially those published prior to 1990.
4. Knowing More Than The Casual Bookseller: Caldecott Illustrators
Most booksellers know the most popular children's picturebooks illustrators - Seuss, Sendak, Silverstein, Carle, Van Allsburg - therefore there is high competition for their valuable books, and a plethora of first editions of their later books on the market (as they become more and more popular their first edition print runs were ginormous). There are a number of less well-known illustrators who have high collectibility yet their books did not cross over into pop culture like their more popular peers.
There are too many to list however the Caldecott's are again another solid source. Learn of the illustrators who have won multiple Caldecott awards - both Medal and Honor - and be on the lookout for early or first editions of their works. In general, once an illustrator wins a Caldecott award, whether thay authored the award book or not, they become more marketible from a publisher's perspective and post-award will both author and illustrate their books in order to recieve both pieces of the royalty pie.
- From the 1940s's there's Virginia Lee Burton, Marjorie Flack, Wanda Gag, Berta & Elmer Hader, Robert Lawson, Lois Lenski, Robert McCLoskey, Clare Turlay Newberry, Tasha Tudor, Maud & Miska Petersham, Leonard Weisgard, and Kurt Wiese.
- From the 1950's there's Marcia Brown, William Pene du Bois, Roger Duvoisin, Margeret Bloy Graham, Crockett Johnson, Marie Hall Ets, Leo Politi, Mark Simont, and Taro Yashima.
- From the 1960's there's Ed Emberley, Paul Galdone, Nonny Hogrogian, Ezra Jack Keats, Leo Lionni, and Evaline Ness.
- From the 1970's there's Nancy Ekholm Burkert, Barbara Cooney, Donald Crews, Leo & Diane Dillon, Richard Egielski, Tom Feelings, Susan Jeffers, Arnold Lobel, Beverly Brodsky McDermott, Gerald McDermett, Peter Spier, Ed Young, and Margot Zemach.
- From the 1980's there's Molly Bang, Tomie DePaola, Stephen Gammell, Diana Goode, Trina Schart Hyman, Peter Parnall, Peter Sis, Uri Shulevitz, William Steig, and Paul Zelinsky.
- From the 1990's there's Allan Say, Mordecai Gerstein, Kevin Henkes, Jerry Pinkney, Chris Raschka, Eric Rohmann, David Shannon, Janet Stevens, and David Wiesner.
- Post 2000 there's Bryan Collier, Tony DiTerlizzi, Mary GrandPre, Molly Idle, Jon Klassen, Jon Muth, Kadir Nelson, Marjorie Priceman, Laura Vaccaro Seeger, Brian Selnick, David Small, Mo Willems, and Pamela Zagarenski.
5. Learn To Read: Transitioning from Dick, Jane, and Spot.
During the late 1950's and throughout the 1960's the nation transitioned from academically prescribed and published early readers to commerical learn-to-read books. The two most popular and collectible are Random House Beginner Books and Harper's I Can Read. Early and first editions of these books in DJ's are very sellable on eBay.
Both Beginner Books and I Can Read books with a DJ price of $1.95 indicates they were published prior to 1970. The 1970's and 1980's Harper I Can Read books will normally have a number line therefore the edition is fairly easy to discern.
I hope this helps.
