When a SQL Server database is operating smoothly and performing well, there is no need to be particularly aware of the transaction log, beyond ensuring that every database has an appropriate backup regime and restore plan in place. When things go wrong, however, a DBA's reputation depends on a deeper understanding of the transaction log, both what it does, and how it works. An effective response to a crisis requires rapid decisions based on understanding its role in ensuring data integrity.
I read this book front to back and it's really good. Every DBA-in-spe or oldtimer should read this because it clarifies a lot of mysteries about the log file. It gives specific answers and nice examples to proof its point. There is a lot of BS to read in forums about the transaction log file, about what to do and not to do with it. Read this book and you will know what to do. The book contains a lot of links to other free books and articles.
Many congratulations for the authors and thank you for making it available for free.
Another book I originally read about 5 years ago, but am revisiting. This is actually one of the free ebooks you can get from Redgate Software. I think I picked this copy up at the Redgate booth at TechEd Houston back in 2014. Let's just say that 208 pages about SQL Server Transaction Logs are just about as in-depth as you are going to get on the subject. Easy to read and follow. I especially large the larger font for these older eyes. My favorite part is Chapter 2 discussing Virtual Log Files which has always just escaped my understanding. But in this book, the examples and explanations were the best I have seen and allowed me to finally get the concept. Thank you, Tony, Gail, and Kalen.