Two book series that hit the nail for us are the series of Enid Blyton, like Famous Five, (we read to them at age 8-9) and Jeff Kinney's Diary of a Wimpy Kid (t

Two book series that hit the nail for us are the series of Enid Blyton, like Famous Five, (we read to them at age 8-9) and Jeff Kinney's Diary of a Wimpy Kid (they read by themselves). Especially the later is a masterpiece for (pre)puberty age. Days upon days of intellectual and emotional satisfaction.