Ahkaam e Tajweed provides the adaab(rules) of reciting the Holy Quran.
The meaning of the verse / ayah can be changed if the letters are not pronounced correctly. Thus it is important to recite every letter of the Quraan properly with all of its rules and properties.
Hazrat Ali (R.A) said:
ان علم التجويد هو تجويد الحروف ومعرفة الوقوف
Ahkaam e Tajweed is complete guide to understand all ahkaam/rules which are neccessary for recitin Holy Quran. The most important part of Tajweed is learning about correct position of the organs of speech and the manner of articulation.