We got this for my son when he was 21 months old. He immediately loved it and it kept his attention longer than any thing else. He was able to figure out the puzzles pretty easily and his only difficulty was with the triangles (they are not equilateral so they have to go in a certain way). The triangle actually presented a great opportunity to teach him to keep trying and not give up, even when it doesn't go right in. By the time he was 2 he had completely mastered it and has moved on to harder pattern block sets. He is now 2 years 3 months and is working on pattern blocks recommended for ages 4+ (He mastered the next level pretty quickly as well, we just keep getting a harder set, the most recent set is progressively harder so it should grow with him more). This was a great introduction (and he still loves to get this one out to this day) and I would recommend parents to get this at ~18 months and just try it. This helped my son focus on an activity, learn his shapes (saying the words), learn to combine shapes to make a larger one (2 triangle=1 square, 2 squares=1 rectangle in this set), learn to get past learning frustrations and keep trying, and generally introduce him to pattern blocks. Overall great educational toy.