I would happily recommend this set of books for even the youngest of children.
They are lovely and sturdy, with inset letter(s) on each page for your child to put their finger in and trace the shape, but most importantly they don't seem like an "educational" book to children! Even without focusing on the phonics element to the books, the pages are great fun to look at just for the pictures - there are recurring characters (eg a snake) which can be searched for on each page, and 2-4 pages at the rear of each book with exercises such as matching games, some with flaps to lift, which re-inforce the sounds covered in that book.
Because of these elements, my little girl (then aged 2) enjoyed looking at them just as much as my 4 year old son, who'd just started in reception class at school when I bought these 6 months ago to supplement his learning to read. My only wish is that I had bought them 2 years before when he was a pre-schooler, as it would have introduced the jolly phonics concepts that he is now learning at an earlier age.
Highly recommended to all.