The ninth and tenth books in the series, Rook Wood and Moon Landing, use only decodable regular words made up from the first five groups of letter sounds:
s, a, t, i, p, n
c k, e, h, r, m, d
g, o, u, l, f, b
ai, j, oa, ie, ee, or
z, w, ng, v, little oo, long oo
Tips and guidance for teachers and parents are provided at the end of each book. Light type is used as a guide for those few letters that should not be sounded out, such as the /b/ in ‘lamb’.