The 'Reader Rabbit' series, in its original PC game heyday, was pretty clearly aimed at preschool through early elementary school kids, I'd say roughly ages 3 to 7. Those were foundational literacy tools, not storybooks for independent reading. The software's main focus was on letter recognition, basic phonics, simple spelling, and beginning word comprehension through interactive mini-games.
My nephew was about four when he got hooked on 'Reader Rabbit's Preschool'. He couldn't read at all yet, but the games with matching shapes, colors, and hearing letter sounds were perfectly paced for him. By first grade, he'd moved on to 'Reader Rabbit's 1st Grade', which had more complex activities like putting sentences in order or simple math. The progression in difficulty across the different titles ('Toddler', 'Preschool', 'Kindergarten', '1st Grade', etc.) was the real clue to the intended age bracket.
While the brand expanded into some physical books and videos, the core interactive learning experience was designed for that pre-K to early grades window. The tone is cheerful and supportive, the challenges are bite-sized, and the rewards are immediate—classic early childhood edutainment structure. A kid who's already a confident reader in third grade would likely find it too slow, but for the target group, it was a great bridge between play and structured learning.
I sometimes see the old CDs at thrift stores and feel a wave of nostalgia, though they're practically relics now. The specific age fit was always its greatest strength.