I can definitely recommend that if you're interested in the topic. A pretty detailed exploration of the Kurgan Hypothesis.
We know much about Proto-Semitic AND Proto-Afro-Asiatic, thankfully, due to the antiquity of recorded Semitic languages in the Near East. Proto-Austronesian seems to be clear too with the 600+ languages we have access to. Unfortunately the languages between the three (Caucasians, language isolates, Tibeto-Burman, Andamanese, Turko-Mongol-Yeniseian Altaic* sprachbund etc) are much more obscure.
Yeniseian (the originator of such words as Tengri, Kha(g)an, etc) being connected to Native American Apache language was pretty amazing and evidence of the importance of paleo-linguistics in finding out informations about our ancestors
This is a bit controversial, though. I haven’t read through the original papers, but one person who did so informed me that they found this relationship not very convincing at all. Still, it’s fascinating stuff!
Vajda’s theory is still regarded as very tentative by the community, and even Vajda himself suggests in his most recent book on the subject that work towards proving a connection has barely begun. It is definitely not settled science.
However I do not believe your comment about the “vast majority” of languages is accurate. I indo-European languages make up about half of all languages on the planet (3.2 billion) and no other language family comes close.