This thesis contains results about the embeddings of M ̈ untz spaces in the Hilbert space scenario and its applications to composition operators on M ̈ untz spaces. In the main, we shall be concerned with the embedding M Λ 2 ⊂ L 2 (μ), where the Hilbert- M ̈ untz space M Λ 2 is the closed linear span of the monomials x λ n in L 2 ([0, 1]) and μ is a finite Borel measure on [0, 1]. After gathering together the mathematical preliminaries required for this work in Chapter 1, we shall use the notion of a sublinear measure introduced by I. Chal- endar, E. Fricain and D. Timotin [8] to investigate the properties of boundedness, compactness and belonging to Schatten-von Neumann ideals of these Hilbert space embeddings. This will be the content of Chapters 2 and 3. In Chapter 4, we give ex- amples of sublinear measures for bounded and compact embeddings with interesting properties. Finally, in Chapter 5 the general embedding theory is applied to initiate the study of composition operators on M Λ 2 .