Poorly organized and lacking in any meaningful content, this book is more of a recap of good overall teaching strategies. More of a collection of common sense teaching practices, the book is unduly burdened with research into mundane facts that some doctoral candidate might have seized upon as a good dissertation because topics in this field are so overly researched. The findings: students who have teachers that teach them academic language are more successful academically than those who do not. Really? No kidding. You mean people who don't understand what they're reading, don't do well on exams of the content of their reading? Why didn't we think of that sooner.
After the initial phase of justifying the existence of this book, the authors move on to a host of strategies that are meant to foster academic language development. As usual with books of this kind, the examples are extremely poor and probably not really applicable in real life. One of the standout examples involved teaching about the transcontinental railroad by clearing the center of your room, building fake obstacles and having students use popsicle sticks laid end to end to simulate the building of the railroad. The activity probably takes the greater part of 35-40 minutes and has NO content value whatsoever. Sure students will be talking, but about the content? Unlikely.
If you want a better book on applicable teaching strategies, try Doug Lemov's Teach Like a Champion. The strategies are presented in a shorter, more approachable way and the research smattered throughout is relevant: why this strategy works and is valuable. Period. As to teaching English Learners, good teaching strategies that address vocabulary building are good for ALL students, not just ELs. Whether people are native English speakers or not, there's a need to introduce new, higher level vocabulary in each discipline, at every level of education. Otherwise, what's the point of going to school? You could just read Wikipedia all day.