'Tattvabodha' means knowledge,bodha,of reality,tattva.'Tattva' means generally the 'ness,'the essential nature of anything the truth of it.Here,it is used in the sense of the ultimate truth.When we say that tattva is the ultimate truth,there is definitive meaning for it. Tattvabodha helps you appreciate the beauty,profundity and vastness of the vision of Vedanta. Trust this will suffice.