The ability to combine and arrange formal and meaningful units is an unquestionable advantage that languages have in comparison to other communication systems. If we want to know how languages work, we must understand how they make use of this combinatory potential and what its limits are. This book analyzes the occurrence and combinations of phonemes in Modern Standard Czech, which is known for exploiting the combinatory potential of formal units to a high degree. The analysis comprises more than 500 combinations of consonants as well as combinations of vowels and consonants within the so-called distributional unit – a phonotactic model superior to the syllable. It also presents a way to predict structurally possible but actually unattested combinations with this model.