The chapters of this reprint cover a wide range of topics related to the theoretical aspects of artificial intelligence (AI) and machine learning (ML), as well as their practical applications. The theoretical aspects presented in this reprint are related to model compression, interpretable AI, effective augmentation strategies, time series analysis, etc., but most of the works are applicative and multidisciplinary. The applications include but are not limited to, medical image processing, natural language processing, time series analysis, diffusion model-based music generation, autoencoder applications, and adversarial learning, to name a few. By compiling such a diverse set of articles, the reprint aims to serve as a resource for researchers and AI enthusiasts and to offer them insights into the latest advancements and diverse applications of AI and ML. This reprint includes 26 articles accepted and published in the Special Issue "Artificial Intelligence and Machine Learning Based Methods and Applications, 2023" of the MDPI "Mathematics" journal.