Cons: usefulness will depend on how much you already know about worldbuilding
This is a book of essays Brennan wrote for her Patreon backers. It consists of 51 short (1-3 page) essays on a range of topics useful for worldbuilding. As an anthropologist with an undergraduate degree in archaeology and folklore and several fantasy novels under he belt, she’s uniquely qualified to write this. And this book covers a wide variety, from the basics of the world (mountains, rivers, deserts), to food (including where it comes from and where it’s prepared), names, folk magic, stages of life, money and more. She’s also written an introduction and conclusion to tie the book together.
The essays are designed to get you to think outside the box by first showing you the box is there. She often asks questions about why we do things a certain way and points out that people in other cultures and periods do/did things differently. Some of what she mentions is obvious in hindsight, but you often need things like this pointed out if you’ve only got one frame of reference. I learned several fascinating tidbits and it was interesting to see the examples from other cultures she used.
The essays are quite short making it easy to get through the book and get back to writing. If you’re commuting and want something short, this is perfect. I read it as a novel, but it’s equally easy to read just the segments you need at a given time.
This is a great resource if you’re new to worldbuilding or haven’t learned to question why people act they way they do in all aspects of life. The essays are varied and, though short, contain a lot of information. If you want your secondary world to feel real, there’s a lot of good pointers here.