Good books on unsupervised learning
There might not be an entire book about unsupervised techniques, given the greater effectiveness of supervised learning techniques. However, there are small books and selected chapters from longer books that could be relevant:


"Unsupervised Machine Learning in Python" which includes Gaussian Mixture Models
"Python Machine Learning" which has a section on Latent Dirichlet allocation (LDA)
"Modeling Techniques in Predictive Analytics with Python and R: A Guide to Data Science" which has a chapter on Market Basket Analysis
"R for Marketing Research and Analytics" which covers Confirmatory Factor Analysis and Structural Equation Modeling