Just got finished with another one of my Christmas knitting books – Yarn Substitutions Made Easy by Carol Sulcoski. This book pretty much tells you exactly what it’s going to do right there in the title.
The author starts off with yarn fundamentals, and goes over all the different factors that make yarns unique. She talks about how to find the characteristics of the yarn that is recommended in a pattern, and how to use that information to pick out yarns that will be a good substitute.
The theoretical information is followed up with some simple patterns, where she takes you through the exercise of looking at the recommended yarn, and figuring out good substitutes. The end of the book even has nifty worksheets you can use to document your own adventures in yarn substitution!
I know I have had difficulties in substituting the recommended yarn for another one. Mostly because I was just worried about gauge, and not about other factors like drape, elasticity, or any of the other things that influence how your project will turn out. If you like to replace recommended yarns with your own choices, you may want to check out this book. Handy!