Halfway Station Presents... is a series of anthologies of (chiefly) magazine articles written by Andy Slack and republished in anthology form by Slack and made available free of charge on the Internet.
The anthologies consist of articles about a particular game (Traveller & 2300AD chiefly). The articles consist of game advice, alternate rules, and scenarios.
Halfway Station is the name of Andy Slack's gaming blog. The anthologies are not available directly from his blog, however, but may be found at several fan-sites.