The Valley of the Cobras
by Hergé; trans. Leslie Lonsdale-Cooper & Michael Turner (Casterman, 1957)
In this final book of the series, Hergé at last strikes the right balance, giving free reign to slapstick antics while more or less side-lining Jo and Zette (though still depicting them as adventurous mini Tintins; Jocko serves as a surrogate Snowy).