[hrothgar]

Quick comment:

There are a lot of different schools of thought regarding overcalls on a 4 card suit. Regardless of which school your studying, be sure to understand the basic bidding philosophy used by that school.

Case in point: As many people have noted, Marshall Miles is a well known proponent over overcalling on 4 card suits. However, a very large percentage of his example hands contain a 4 card major with a longer minor. I don't want to start a debate regarding the relative merits of this overcall style compared to either raptor NT overcalls or nebulous takeout doubles or wide ranging passes. I am simply suggesting that its useful to understand WHY different authors advocate a particular set of bidding methods.

For what its worth, I play lots of systems based on opening 4 card majors. I like being able to introduce my major suits as quickly as possible. Not too surprising, I'm perfectly comfortable overcalling on a 4 card major for much the same reasons. When I am considering overcalling a 4 card major, my primary consideration is based on bidding space. A 1♥ overcall of a 1♦ opening gives the opponents more bidding space than they had available previously. Accordingly, I tighten up my overcalls in situations like this.