Minicourse for PhD and master students. Title: Deformations of Fano and Calabi-Yau varieties. Abstract: In the classification of algebraic varieties, we parametrize varieties with similarities, thus it is natural to consider families/deformations of varieties. In good cases, we can parametrize some varieties over a smooth base space and this makes the description of the moduli space of those varieties reasonable. Fano varieties and Calabi-Yau varieties are fundamental objects in the classification. In the talks, I'll explain that, when varieties are Fano or Calabi-Yau, we have such smooth parameter spaces. In most parts, I'll concentrate on smooth Fano/Calabi-Yau varieties. If time permits, I'll also talk about more general cases.