The Russian Lullaby: Books/ Drupal 9 Module Development

For a long time I was thinking about write or not a review of the Drupal 8 Module Development (the former edition of the current). For me there were two very important keys: on the one hand, it was a very ambitious book in terms of scope and content (so it was an important challenge to make a synthesis on its simple review). On the other hand, Drupal 9 was already on its way and it was possible that it would be deprecated quickly. Luckily, Drupal 9 has already arrived and the transition from 8 to 9 has not only not been at all traumatic (there are still many people trapped in the crack between …