Most researchers would relate X-ray structure analysis to crystal structure analysis. A crystal is a state in which atoms or molecules are regularly arranged in three-dimensional space. However, some substances do not have 3D structures, but have 1D, 2D, 1D⊕1D, 2D⊕1D or 1D⊕1D⊕1D structures. Here the symbol ⊕ stands for direct sum in linear algebra and is different from ordinary sum +. For example, 2D⊕1D means the direct sum of a 2D subspace and an orthogonal 1D subspace, not 3D.In a previous book, Physics and Chemistry of Molecular Assemblies, published in April 2020, the author showed for the first time that molecular assemblies can be represented in a unified manner from such subspaces of linear algebra, and wrote the theory and method of X-ray structure analysis of the liquid crystal phase structures with the dimensional structure of 1D, 2D, 1D⊕1D, 2D⊕1D, and 1D⊕1D⊕1D. Furthermore, the X-ray liquid crystal structure analysis methods of 11 representative examples were concretely described. In addition, 110 X-ray data were posted as the end-of-chapter problems in Chapter 3.