Best Workbooks for Kids?

Most preschoolers don't enjoy workbooks or worksheets, that's more of a late kindergarten/first grade activity.
At four he will learn best HANDS ON: lots of sorting and counting (coins, beads, etc.) Puzzles and unit blocks are great for spatial learning, as is measuring, have him help you cook!
Reading and singing ABC books and songs will help with letter recognition. Reading out loud to him and then talking about what you just read and asking questions will strengthen/enforce comprehension skills.
Another very important thing at this age is to make sure he gets lots of fine motor skill practice: cutting, drawing, gluing, lacing, painting, all of these will prepare him for writing in kindergarten.
Most of all? Have fun!!! He has at least 13 years of school ahead of him, there will be plenty of workbooks in his future.

walmart has school zone work books like the preschool workbook i started my daughter on it at age two and she just turned 3 she loves school witht that book i also went to the dollar tree they have alot of great work books there as well.

I would recommend any that are "wipe off" and can be used with a dry erase pen. that way, you can do them over and over if there are certain skills that need more work.

that said, 4 year olds don't really need to be doing workbooks at all. he can practice all of those things in other, more fun, ways. Get him chalk and crayons. Have him write letters to his teachers, friends, grandparents, etc. Play a game and have him write down the scores.

Mead makes neat workbooks with the lined paper indented to really teach kids to write their letters and numbers between the proper lines. They have the dotted numbers and letters that they can trace, and then blank sheets for practice. They go by age/grade... I always buy them for my daughters during the summer to keep their brains sharp ;) I buy mine from Target for about $4 or $5 each...

ETA: This is very similar, the one's I buy actually have instructions:

http://www.target.com/p/100CT-MEAD-PRIMARY-COMPOSITION-BK...

I've been buying workbooks for my now 6 yo at Toys R Us and Walmart over the past few years - letters, numbers, phonics, dot to dot (for fine motor skills) and cognative excercises (hidden pictures, big/bigger/biggest). They are School Zone books.

We also use books from Spectrum, Teacher Credited Resources and American Education Publishing for beginning math and reading. You can find them online or at any teacher supply store.

gl