I love Jethro Tull at their most baroque, and that’s how they’re best known. But they did used to be a blues band, back in the 60’s. It seems that nearly everyone who started out in the 60’s was initially a blues band, and some groups evolved from there better than others. In J-Tull’s case, blues rock was clearly too narrow a field to stick around in for more than a year or two. Never the less, they did it well. It’s a good rule of thumb that you shouldn’t jump out and experiment if you haven’t first mastered the basics, and This Was was, perhaps self-consciously, a starting point before the stride towards more wildly ambitious things.