Have you ever read a book on second language (L2) learning and thought to yourself that the book was overburdened with academic jargon about theory and esoteric topics? Have you ever wondered about what is usually used in L2 reading and whether it actually works? This book serves as the definitive reference for the topic of the effects of glossing on L2 reading comprehension. No other book comes remotely close. We discuss glossing studies that have shown a positive and negative effect of glossing on L2 reading comprehension and vocabulary learning, along with providing a more general statistical perspective. Overall, the first section outlines variables influencing L2 reading comprehension. The next describes glossing and L2 learning theory, reading comprehension and vocabulary learning. The final section contains chapters on strategy training and testing, arguing that strategies and tests can be useful in improving and measuring L2 reading.