Miguel Grinberg's "Flask Web Development" [1] is an excellent introduction Python-based web development. You build a Twitter-clone. The book is an adaptation of the authors 18-part tutorial on the same topic [2]. [1] http://shop.oreilly.com/product/0636920031116.do [2] https://blog.miguelgrinberg.com/post/the-flask-mega-tutorial...
Remark that the article is rather old (although revisited 2014, however that's still an eternity in webdev world). Although I like flask (it was my first library to do "web stuff") I miss especially the fact that authentication is not part of the core lib, but only available via third-party extensions. That may not be a problem for an experienced dev, but for a starter in web-dev I highly appreciate a library or fram…
But yes, definitely grab a third party extension for auth :)