The more you struggle to understand something, the more memorable it becomes.
This book is a great workbook for advanced learners. It provides a lot of exercises that compare similar grammatical items that connect two sentences, such as 時 (when) and 〜たら (when/if).
The book is designed for you to discover and understand grammar rules and nuances of use through practicing and interacting with the grammar, rather than just reading an explanation. Each section starts with a simple warm-up quiz, followed by slightly more challenging questions. Then it gives you a simple and concise explanation of the grammar, without diving into the nitty-gritty details. After that, it offers more exercise about the items to help you deepen your understanding.
If you are looking for a well-explained grammar textbook, this isn't for you. They give you key points, but you are the one who deepens your understanding through problem-solving by yourself. According to neuroscience, the more you struggle to understand something, the more memorable it becomes. So give it a try if you're up for the challenge!