I have met Szymon Dolecki at the Summer Topology Conference 2016, and he is a charming person. In 1995, with Gabriele Greco and Alojzy Lechicki, he proved a very nice theorem — every Čech-complete space is consonant — that deserves to be well-known. As a coincidence, this very theorem was mentioned by Jimmie Lawson at the same conference. It is also the subject of Exercise 8.3.4 in the book, but I am afraid that, as stated, it is way too hard. My purpose here is to give a complete solution to the exercise. The proof is elementary, that is, it does not require any deep knowledge of topology. Read the full post.