I read Pihkal before, and didn't know whether Tihkal would bring anything new. But it did.
This book is highly recommendable for those who liked Pihkal. The book does not repeat what has been said before, but goes on with more experiences.
Towards the end of the first part, there is, for the non-botanist, a bit much about plants and the biology and chemistry of them. But for the rest, still highly interesting!
The second, chemical, part of course is for chemists. So, like with Pihkal, I just cut the book in the two halves and highly enjoyed the first part.