I own this book and have brewed a bunch of batches of beer from it back in the late 80's early 90's. The all malt recipes are generally better than the extract recipes, and the author has a tendency to use a lot of adjuncts (esp. brown sugar in his recipes). Nevertheless, you can adapt them to make them come out quite well from a malt perspective. I generally used dry malt extract instead of the sugars he calls for.
On the other hand, virtually all of these beers come out too bitter if you use his hop levels. This is largely because hops are better processed and stored now than in the late 60's early 70's when the book was written. Also, our varieties have adapted to have higher AA levels making them more bitter. So if you take some of his recipes and put them into BeerSmith (software to calculate recipes), most of the mild ales come out having 25-40 IBU. Many Special and Best bitters from the book have upwards of 50-80 IBU -- again for English bitters, too hoppy and they won't taste like the beer they are mean to imitate.
So I'd aim for using ~2/3rds the hops called for many of the recipes -- you'll still be over the conventional IBU level for most style, but it will be drinkable.