This book is an updated compilation of sandalmaking directions and patterns from my two previous sandalmaking books. It goes into detail about how to make ecological sandals – the materials I suggest you use are vegetable-tanned leather for straps, and vegetable-tanned leather, natural rubber, and upcycled soling materials such as conveyor belt for bottom soles. Non-toxic cement is used to adhere the sandal layers together, so the soles need to be stitched together.
The styles you can learn to make include a continuous-strap gladiator sandal and continuous-strap traditional-style sandal, a flip-flop with a stabilizing band across the instep, a two-band sandal, a loop sandal and one-strap sandal.
Once you have mastered a few of these styles, and have looked at all the sandals on my Pinterest board, https://www.pinterest.com/simpleshoemaker/sandals-and-other-things-to-inspire-the-making-of-/, you can be ready to design your own. If you make just a few styles, like the couple who gave me the gladiator sandal pattern did, you could develop a nice business as there are very few sandal makers working today.