As you can imagine, the causes of WWI and the events leading to it are a pretty hot topic. It, and the aftermath, created a lot of the modern world, and so a lot of the problems of the modern world, and so a lot of people have had something to say about it. The number of books written on WWI is huge. Tuchman's book, while very readable and not terrible, is a bit old, now. It suffers from some of the convictions of her time: that almost all British officers were donkeys, for example. It also didn't pay that much attention to the Balkans, where the spark was lit and where there actually also was a war. Read Tuchman and you might suddenly wonder, wait, weren't there Serbs involved in kicking this thing off? ( and if you then picked up Christopher Clark's more recent Sleepwalkers, you might also think, wait, weren't there Germans involved in kicking this thing off?) If you'd like a recommendation of more current reading, u/DuxBelisarius posted a summary of the issue here