Genan gives 155 of these positions. Page 1, above, shows four. There is sparse comment, and he does not explain his method. There is no obvious structure. At first glance, therefore, the book seems rather unsatisfying, at least to the modern taste. Nevertheless, if the reader is prepared to engage actively with the examples, not waiting to be spoonfed, it soons becomes apparent that there is indeed some sort of structure. The apparent repetitions mask nuances that are always worth pursuing. Moreover, the examples turn out to provide a pretty comprehensive coverage of the commonest positions. There is a nice blend of utterly simple and rather neat plays. Perfect for the amateur reader.