"In many ways Europe was more completely shattered by the first than the second world war, and this book captures the atmosphere of that period very well." It's not clear to me what meaning we should attribute to the word a 'shattered' used like this. WW11 caused a level of material destruction that was far, far greater than WW1 - there is no doubt about it. Germany was a ruin, with bombed out cities and barely functioning industry. Poland too hasd seen terrible destruction to its infrastructure. Many British and French cities had been badly bombed.
If you are referring to the social and political chaos after WW1 being greater than after WW11 you could have an argument but only just.