Benedict Pictet

I haven't yet read it all, but I'm prepared to say that Benedict Pictet's Christian Theology is perhaps the best overall systematic theology in existence.

Of course all the great Reformed, Calvinist STs give roughly the same doctrine, in different styles and to different degree of depth or conciseness, but Pictet seems to me to be right in the golden mean of overall depth, especially if you are at the point of using a theological work for meditation and prayer and devotion. 

It's only available in eBook at Monergism.com. That I know of. 

It's a summation of the true Genevan school of Calvin. Maybe the final work of that school. I know Turretin is thought of as that, but I'm not saying Pictet is the last word in theology. Bavinck, a Brakel, Vos, Turretin, etc., just if you're looking for a one volume summation that is old path, complete, basic, and gives evocative yet plain prose for meditation and memory of doctrine I think it's perhaps the best I've seen.

Ultimately a simple, powerful Christian library should not be large. It should be able to fit on a small shelf. Our days are numbered.