This book is fantastic, and per the title, absolutely the first thing I reach for when I need to develop or design transaction systems. Be aware that this book is what it claims to be on the cover. It will likely be interesting to people using a database or other transactional system, but is unlikely to be directly relevant. Instead it is focused on the theory you need to know if you are developing or designing such a system, and here it excels. As it is out of print pdf's of the individual chapters are available online, however after my printouts fell apart for the second time I tracked down a second-hand copy and highly recommend readers do the same.