Ruhlen lets the monolingual English reader classify the world's languages. See for yourself the linguistic and genetic evidence supporting superfamilies and monogenesis. Make it your next read.

"This volume surveys the progress of the genetic classification of languages over the years, records recent developments, and points to abundant opportunities for further research."

Behold! Greenberg's final contribution to comparative linguistics.

Planning a Native American conlang? Greenberg's "Amerind" family is still controversial, despite long-established multidisciplinary corroboration. Hundreds of etymologies. More in #2 above.

The most complete list of IE roots I've found, despite omissions. Many cultural notes are also included. If your conlang is Indo-European (ad nauseum!), this dictionary will really help.

Very technical but full of PIE reconstructions of beliefs, values and other themes expressed in poetic formulae. Indispensable for epics, sagas, spells, or scriptures of the IE form. Not for amateurs.

The comparative method as applied to the IE family. Doesn't mention relationships among IE daughter families nor IE to its sister families, but it's nice to have a variety of sources.

Kudos! Excellent! Sums up (pre)history since the agricultural revolution. Answers "Why did history unfold differently on different continents?" Explains fateful cultural advantages and disadvantages.

What's a religion, language, or society without myths? Reliably covers many myths and themes exclusive to IE cultures, explaining their linguistic context. Far more precise than Campbell.

'Nuff said!